Bitcoin Wiki - User contributions [en]

How to get free Bitcoins?

2014-03-26T09:11:36Z

Dth123:

There are several websites offering free Bitcoins to anyone. One major site doing this was the [[Bitcoin Faucet]] (closed as of the time of this writing).

If you [http://lmgtfy.com/?q=free+bitcoin google for Free Bitcoin], you should be able to find some working site.

==External Links==

* [http://www.vnbitcoin.org/freebitcoin.php Vnbitcoin FreeCoins] site, 0.00003 Bitcoin once per visitor.
[[Category:Services]]

How to get free Bitcoins?

2014-03-26T09:07:39Z

Dth123:

Bitcoin faucet

2014-03-26T09:06:38Z

Dth123:

Used to gives bitcoins out for free to each visitor. IP addresses that receive bitcoins were recorded, so that bitcoins were given only once to each address. It was operated by [[User:Gavinandresen|Gavin Andresen]], however it is not functioning as of Jan 30 2013.

For [[Testnet]] there exists a different faucet that is working which gives out coins for people who want to do tests on the Testnet. The testnet faucet also has a simple wallet available to hold testnet coins.

==See Also==

* [[Trade#Getting_started|Alternate bitcoin distribution services]]

==External Links==

* [https://www.pikapay.com/bitcoin-fountain Bitcoin Fountain] New type of faucet pays out in seconds to all established Twitter accounts.
* [http://freebitcoins.appspot.com Bitcoin Faucet] web site
* [http://tpfaucet.appspot.com/ TestNet Faucet] web site
* [http://faucet.xeno-genesis.com/ Mojocoin Testnet3 Faucet] web site
* [http://faucet.luis.im/ luis.im Mojocoin Testnet3 Faucet] web site
* [http://freecoins.herokuapp.com FreeCoins] site, 0.00005 Bitcoin payouts sent every day, faucet can be used once a week.
* [http://www.vnbitcoin.org/freebitcoin.php Vnbitcoin FreeCoins] site, 0.00003 Bitcoin once per visitor.
[[Category:Services]]

Bitcoin faucet

2014-03-26T09:02:01Z

Dth123:

Difficulty

2014-03-25T11:00:50Z

Dth123:

''See also: [[target]]''

=== What is "difficulty"? ===

Difficulty is a measure of how difficult it is to find a hash below a given target.

The Bitcoin network has a global block difficulty. Valid blocks must have a hash below this target.
Mining pools also have a pool-specific share difficulty setting a lower limit for shares.

=== How often does the network difficulty change? ===

Every 2016 [[block|blocks]].

=== What is the formula for difficulty? ===

difficulty = difficulty_1_target / current_target

(target is a 256 bit number)

difficulty_1_target can be different for various ways to measure difficulty.
Traditionally, it represents a hash where the leading 32 bits are zero and the rest are one (this is known as "pool difficulty" or "pdiff").
The Bitcoin protocol represents targets as a custom floating point type with limited precision; as a result, Bitcoin clients often approximate difficulty based on this (this is known as "bdiff").

===How is difficulty stored in blocks?===

Each block stores a packed representation (called "Bits") for its actual hexadecimal [[target]]. The target can be derived from it via a predefined formula. For example, if the packed target in the block is 0x1b0404cb, the hexadecimal target is
0x0404cb * 2**(8*(0x1b - 3)) = 0x00000000000404CB000000000000000000000000000000000000000000000000

Note that the 0x0404cb value is a signed value in this format. The largest legal value for this field is 0x7fffff. To make a larger value you must shift it down one full byte. Also 0x008000 is the smallest positive valid value.

The highest possible target (difficulty 1) is defined as 0x1d00ffff, which gives us a hex target of
0x00ffff * 2**(8*(0x1d - 3)) = 0x00000000FFFF0000000000000000000000000000000000000000000000000000

It should be noted that pooled mining often uses non-truncated targets, which puts "pool difficulty 1" at
0x00000000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

So the difficulty at 0x1b0404cb is therefore:
0x00000000FFFF0000000000000000000000000000000000000000000000000000 /
0x00000000000404CB000000000000000000000000000000000000000000000000
= 16307.420938523983 (bdiff)
And:
0x00000000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF /
0x00000000000404CB000000000000000000000000000000000000000000000000
= 16307.669773817162 (pdiff)

Here's a fast way to calculate bitcoin difficulty. It uses a modified Taylor series for the logarithm (you can see tutorials on flipcode and wikipedia) and relies on logs to transform the difficulty calculation:

<source lang="cpp">
#include <iostream>
#include <cmath>

inline float fast_log(float val)
{
int * const exp_ptr = reinterpret_cast <int *>(&val);
int x = *exp_ptr;
const int log_2 = ((x >> 23) & 255) - 128;
x &= ~(255 << 23);
x += 127 << 23;
*exp_ptr = x;

val = ((-1.0f/3) * val + 2) * val - 2.0f/3;
return ((val + log_2) * 0.69314718f);
}

float difficulty(unsigned int bits)
{
static double max_body = fast_log(0x00ffff), scaland = fast_log(256);
return exp(max_body - fast_log(bits & 0x00ffffff) + scaland * (0x1d - ((bits & 0xff000000) >> 24)));
}

int main()
{
std::cout << difficulty(0x1b0404cb) << std::endl;
return 0;
}
</source>

To see the math to go from the normal difficulty calculations (which require large big ints bigger than the space in any normal integer) to the calculation above, here's some python:

<source lang="python">
import decimal, math
l = math.log
e = math.e

print 0x00ffff * 2**(8*(0x1d - 3)) / float(0x0404cb * 2**(8*(0x1b - 3)))
print l(0x00ffff * 2**(8*(0x1d - 3)) / float(0x0404cb * 2**(8*(0x1b - 3))))
print l(0x00ffff * 2**(8*(0x1d - 3))) - l(0x0404cb * 2**(8*(0x1b - 3)))
print l(0x00ffff) + l(2**(8*(0x1d - 3))) - l(0x0404cb) - l(2**(8*(0x1b - 3)))
print l(0x00ffff) + (8*(0x1d - 3))*l(2) - l(0x0404cb) - (8*(0x1b - 3))*l(2)
print l(0x00ffff / float(0x0404cb)) + (8*(0x1d - 3))*l(2) - (8*(0x1b - 3))*l(2)
print l(0x00ffff / float(0x0404cb)) + (0x1d - 0x1b)*l(2**8)
</source>

=== What is the current difficulty? ===
[http://blockexplorer.com/q/getdifficulty Current difficulty], as output by Bitcoin's getDifficulty.

[http://blockexplorer.com/q/estimate Estimated next difficulty]

[http://bitcoin.sipa.be Graphs]

=== What is the maximum difficulty? ===

There is no minimum target. The maximum difficulty is roughly: maximum_target / 1 (since 0 would result in infinity), which is a ridiculously huge number (about 2^224).

The actual maximum difficulty is when current_target=0, but we would not be able to calculate the difficulty if that happened. (fortunately it never will, so we're ok.)

=== Can the network difficulty go down? ===
Yes it can. See discussion in [[target]].

=== What is the minimum difficulty? ===
The minimum difficulty, when the target is at the maximum allowed value, is 1.

=== What network hash rate results in a given difficulty? ===
The difficulty is adjusted every 2016 blocks based on the time it took to find the previous 2016 blocks. At the desired rate of one block each 10 minutes, 2016 blocks would take exactly two weeks to find. If the previous 2016 blocks took more than two weeks to find, the difficulty is reduced. If they took less than two weeks, the difficulty is increased. The change in difficulty is in proportion to the amount of time over or under two weeks the previous 2016 blocks took to find.

To find a block, the hash must be less than the target. The hash is effectively a random number between 0 and 2**256-1. The offset for difficulty 1 is
0xffff * 2**208
and for difficulty D is
(0xffff * 2**208)/D

The expected number of hashes we need to calculate to find a block with difficulty D is therefore
D * 2**256 / (0xffff * 2**208)
or just
D * 2**48 / 0xffff

The difficulty is set such that the previous 2016 blocks would have been found at the rate of one every 10 minutes, so we were calculating (D * 2**48 / 0xffff) hashes in 600 seconds. That means the hash rate of the network was
D * 2**48 / 0xffff / 600
over the previous 2016 blocks. Can be further simplified to
D * 2**32 / 600
without much loss of accuracy.

At difficulty 1, that is around 7 Mhashes per second.

At the time of writing, the difficulty is 22012.4941572, which means that over the previous set of 2016 blocks found the average network hash rate was
22012.4941572 * 2**32 / 600 = around 157 Ghashes per second.

=== How soon might I expect to generate a block? ===
(The [https://www.bitcointalk.org/index.php?topic=1682.0 eternal question].)

The average time to find a block can be approximated by calculating:
time = difficulty * 2**32 / hashrate
where difficulty is the current difficulty, hashrate is the number of hashes your miner calculates per second, and time is the average in seconds between the blocks you find.

For example, using Python we calculate the average time to generate a block using a 1Ghash/s mining rig when the difficulty is 20000:
$ python -c "print 20000 * 2**32 / 10**9 / 60 / 60.0"
23.85
and find that it takes just under 24 hours on average.

* Any one grinding of the hash stands the same chance of "winning" as any other. The numbers game is how many attempts your hardware can make per second.
* You need to know the difficulty (above) and your khash/sec rate (reported by the client).
** [[Mining Hardware Comparison]] has some stats that may help you predict what you could get.
* Visit a calculator or perform the maths yourself,
** http://www.alloscomp.com/bitcoin/calculator.php
** http://www.vnbitcoin.org/bitcoincalculator.php
* Remember it's just probability! There are no guarantees you will win every N days.

==Related Links==

* [https://docs.google.com/spreadsheet/ccc?key=0AiFMBvXvL2dtdEZkR2J4eU5rS3B4ei1iUmJxSWNlQ0E Bitcoin Difficulty History]
* See also: [[target]]

[[Category:Technical]]
[[Category:Vocabulary]]

[[pl:Trudność]]

Mining

2014-03-25T08:17:08Z

Dth123:

[[File:Quick-and-dirty-4x5970-cooling.jpg|thumb|right|A quick and dirty mining rig]]
== Introduction ==
'''Mining''' is the process of adding transaction records to Bitcoin's public ledger of past transactions.
This ledger of past transactions is called the [[block chain]] as it is a chain of [[block|blocks]].
The block chain serves to [[Confirmation|confirm]] transactions to the rest of the network as having taken place.
Bitcoin nodes use the block chain to distinguish legitimate Bitcoin transactions from attempts to re-spend coins that have already been spent elsewhere.

Mining is intentionally designed to be resource-intensive and difficult so that the number of blocks found each day by miners remains steady. Individual [[blocks]] must contain a [[proof of work|proof of work]] to be considered valid. This proof of work is verified by other Bitcoin nodes each time they receive a block. Bitcoin uses the [[hashcash]] proof-of-work function.

The primary purpose of mining is to allow Bitcoin nodes to reach a secure, tamper-resistant consensus.
Mining is also the mechanism used to introduce Bitcoins into the system:
Miners are paid any transaction fees as well as a "subsidy" of newly created coins.
This both serves the purpose of disseminating new coins in a decentralized manner as well as motivating people to provide security for the system.

Bitcoin mining is so called because it resembles the mining of other commodities:
it requires exertion and it slowly makes new currency available at a rate that resembles the rate at which commodities like gold are mined from the ground.

== Difficulty ==
=== The Computationally-Difficult Problem ===
Mining a block is difficult because the SHA-256 hash of a block's header must be lower than or equal to the [[Target|target]] in order for the block to be accepted by the network. This problem can be simplified for explanation purposes: The hash of a block must start with a certain number of zeros. The probability of calculating a hash that starts with many zeros is very low, therefore many attempts must be made. In order to generate a new hash each round, a [[Nonce|nonce]] is incremented. See [[Proof of work]] for more information.

=== The Difficulty Metric ===
The [[Difficulty|difficulty]] is the measure of how difficult it is to find a new block compared to the easiest it can ever be. It is recalculated every 2016 blocks to a value such that the previous 2016 blocks would have been generated in exactly two weeks had everyone been mining at this difficulty. This will yield, on average, one block every ten minutes. As more miners join, the rate of block creation will go up. As the rate of block generation goes up, the difficulty rises to compensate which will push the rate of block creation back down. Any blocks released by malicious miners that do not meet the required difficulty [[Target|target]] will simply be rejected by everyone on the network and thus will be worthless.

=== Reward ===
When a block is discovered, the discoverer may award themselves a certain number of bitcoins, which is agreed-upon by everyone in the network. Currently this bounty is 25 bitcoins; this value will halve every 210,000 blocks. See [[Controlled Currency Supply]].

Additionally, the miner is awarded the fees paid by users sending transactions. The fee is an incentive for the miner to include the transaction in their block. In the future, as the number of new bitcoins miners are allowed to create in each block dwindles, the fees will make up a much more important percentage of mining income.

== The mining ecosystem ==

=== Hardware ===
[[File:Usb-fpga module 1.15x-hs-800.jpg|thumb|right|FPGA Module]]
Users have used various types of hardware over time to mine blocks. Hardware specifications and performance statistics are detailed on the [[Mining Hardware Comparison]] page.
==== CPU Mining ====
Early Bitcoin client versions allowed users to use their CPUs to mine. As the network hashrate grew with more power efficient GPU miners the amount of Bitcoin's produced by CPU mining became lower than the cost of power to operate the CPUS. The option still exists in the reference Bitcoin client, but it is disabled by default.

==== GPU Mining ====
GPU Mining is drastically faster and more efficient than CPU mining. See the main article: [[Why a GPU mines faster than a CPU]]. A variety of popular [[Mining rig|mining rigs]] have been documented.
==== FPGA Mining ====
FPGA mining is a very efficient and fast way to mine, comparable to GPU mining and drastically outperforming CPU mining. FPGAs typically consume very small amounts of power with relatively high hash ratings, making them more viable and efficient than GPU mining. See [[Mining Hardware Comparison]] for FPGA hardware specifications and statistics.
==== ASIC Mining ====
An application-specific integrated circuit, or ''ASIC'', is a microchip designed and manufactured for a very specific purpose. ASICs designed for Bitcoin mining were first released in 2013. For the amount of power they consume, they are vastly faster than all previous technologies and already has made GPU mining financially unwise in some countries and setups.

==== Mining services ====
[[:Category:Mining_contractors|Mining contractors]] provide mining services with performance specified by contract. They may, for example, rent out a specific level of mining capacity for a set price for a specific duration.

Mining shares provide Mining as a Service (MaaS). These break large-scale datacenter mining down to easily manageable pieces that are available in the form of shares of equipment.

Hosted mining services create some systemic risk for the Bitcoin system because they undermine the security assumption that the control of mining power is well distributed. If too much mining becomes consolidated in large hosting providers and an attacker is able to compromise some of these providers they could potentially disrupt the Bitcoin system or rip off people they transact with with reversals.

=== Pools ===
As more and more miners competed for the limited supply of blocks, individuals found that they were working for months without finding a block and receiving reward for their mining efforts. This made mining something of a gamble. To address the variance in their income miners started organizing themselves into [[Pooled mining|pools]] so that they could share rewards more evenly. See [[Pooled mining]] and [[Comparison of mining pools]].

=== History ===
Bitcoin's public ledger (the 'block chain') was started on January 3rd, 2009 at 18:15 UTC presumably by [[Satoshi Nakamoto]]. The first block is known as the [[genesis block]]. The first transaction recorded in the first block was a single transaction paying the reward of 50 new bitcoins to its creator.

==See Also==

* [http://codinginmysleep.com/bitcoin-mining-in-plain-english Bitcoin Mining in Plain English] by David Perry
* [[Automatically mine when computer is locked|Tutorial to automatically start mining when you lock your computer]]. (Windows 7)
* [http://www.reddit.com/r/Bitcoin/comments/18q2jx/eli5_bitcoin_mining_xpost_in_eli5/ Simplified Explanation of Bitcoin Mining] by reddit user [http://www.reddit.com/user/azotic azotic]
* [http://www.vnbitcoin.org/bitcoincalculator.php Bitcoin Mining Calculator]

[[ru:Mining]]
[[Category:Mining]][[Category:Vocabulary]]

Litecoin

2014-03-25T08:09:27Z

Dth123:

== What is Litecoin? ==
Litecoin is an alternative cryptocurrency based on Bitcoin. It differs from Bitcoin in that it targets a faster block rate (2.5 minutes) and uses scrypt for the primary hashing done in mining. MtGox announced in April 2013 that they would add support for Litecoin trading, a plan that was delayed due to recent DDOS attacks.

While scrypt was claimed to be resistant to GPU-based mining early on, GPUs are currently the most efficient hardware with which to mine Litecoins.
One of the aims of Litecoin was to provide a mining algorithm that did not compete with Bitcoin.

In April 2013, Litecoin reached a market cap of $70 million and achieved a network strength above 12 gigahashes/second. This compares roughly to a network strength for Bitcoin of 12 terahashes/second.

== Differences from Bitcoin ==

==== Scrypt Proof of Work ====
Litecoin uses scrypt as a proof-of-work scheme. Scrypt adds memory-intensive algorithms to reduce the efficiency of the kind of parallelization that GPUs offered in early Bitcoin mining. This led to Litecoin primarily being mined with CPUs at the beginning. CPU-based mining has been challenged by the appearance of more energy-efficient GPU-based mining around July/August of 2012 bringing a roughly ten-fold increase in network hashing strength. GPUs are currently the dominant Litecoin mining technology.

Scrypt has been less widely used and analyzed than the SHA2 hashing algorithm used in Bitcoin, so there is some concern about possible weaknesses in its cryptographic scheme being discovered in the future.

==== Faster Blocks ====
The Litecoin blockchain differs from Bitcoin in that it generates blocks every 2.5 minutes on average (four times Bitcoin's rate).
This means that merchants who accept transactions only 1 block deep get that confirmation quicker.
However, it should be noted that more blocks are required to achieve the same amount of confirmation strength as Bitcoin (6 blocks of litecoin are not equivalent to 6 blocks of bitcoin).
Unfortunately, this increases the number of hashes that are wasted in mining since miners will be working from the non-best block more of the time.

==== 84 Million Litecoins ====
Litecoin started with miners generating 50 coins per block as with Bitcoin, but to maintain Bitcoin's inflation rate chage schedule, the block reward gets halved every 840,000 blocks. As a result, the network is scheduled to produce a total of 84 million litecoins.

==== Different Addresses ====

Litecoin addresses start with L due to their version number. Otherwise, they are generated identically to Bitcoin addresses.

==== (Slight) Premining ====
Litecoin had two blocks premined, one more than the minimum single genesis block needed to start a block chain.

==Criticism==
==== Redundancy ====

Besides a faster first confirmation, Litecoin does not provide any other features over what Bitcoin provides.
Because of this lack of innovation, some believe Litecoin is unlikely to match or surpass Bitcoin's value or user-base.
It remains to be seen if the use of a different mining algorithm and faster block times add sufficient value for Litecoin's long-term survival.

==== Not Silver to Gold ====
Some argue that Litecoin cannot make sense as "silver to bitcoin's gold", because Bitcoin itself is both gold and silver:
While in the long-run, the BTC unit may be too valuable for everyday trade ("gold"), there are other, much smaller [[units]] that can just as well serve the purpose of "silver" while being naturally/automatically "converted" to/from BTC.

==== Vulnerability to mining monopoly ====

Similarly to Bitcoin, Litecoin can be attacked by an entity that can match or exceed the hashrate of the network. Such a "51% attack" becomes more difficult to launch and maintain as the hash rate of the network grows. However, this argument posits that Litecoin is designed to be inefficient on all common computer components (both CPUs and GPUs) meaning that a malicious entity need only produce a small batch of specialized/custom hardware to overtake all the commodity mining systems combined.

===== Memory bandwidth refutation =====
Some attempt to refute this by arguing that scrypt is not designed to be inefficient, but is instead designed to be highly dependent on memory bandwidth.
Since the high-speed cache RAM on modern processors already takes up most of the die space, no sizeable improvement could then be made by creating custom chips.
If we accept this argument we then estimate the cost of attack utilizing GPUs that are avilable today.

To do so we start with an estimated cost of hardware at $400 per megahashes per second and the October 2013 Litecoin network hashrate of 30 gigahashes per second.
The total amount of equipment necessary to match and takeover the Litecoin network via 51% attack is then an estimated $12M USD (or about 45,000 AMD HD 7950s).

==== Pump and Dump Scheme ====
According to some, one or more of the aforementioned reasons imply that Litecoin has no future potential, and therefore effectively functions as a [http://www.investopedia.com/terms/p/pumpanddump.asp "pump and dump" scheme], rewarding those who get in sooner at the expense of those who adopt it just before it finally fails (and are left with nothing).

Additionally, people often complain that the Litecoin community misrepresents it in other ways, such as portraying "faster block times" as if it makes transactions faster, and scrypt as if it is resistant to ASIC or FPGA hardware, in order to pretend Litecoin has value and inflate its value.

It's important to note, generally these critics do not think that Litecoin/Blockchain currencies are pump and dump schemes "per se"; but rather that the existing network effect of Bitcoin, combined with the lack of meaningful differentiation between Litecoin and Bitcoin and Litecoin's adoption of a "designed to fail" proof-of-work algorithm; that Litecoin is bound to fail in the end. Bitcoin does not suffer from these "flaws" and therefore does not fall under the "pump and dump" scheme, according to this argument.

==External links==
*[http://litecoin.org/ Litecoin website]
*[http://forum.litecoin.net Litecoin forum]
*[http://explorer.litecoin.net/ Litecoin block explorer]
*[http://ltc.blockr.io/ Blockr.io Blockchain Explorer]
*[http://www.ltc-charts.com/ Charts]
*[http://litecoinscout.com/static/ Litecoin network graphs]
*[https://github.com/litecoin-project/litecoin/wiki Litecoin wiki]
*[https://www.litecoinglobal.com Litecoin Global Exchange (virtual stock exchange)]
*[http://www.crypto.st Crypto Street - Advanced Trading Exchange for Litecoins]
*[http://www.technologyreview.com/news/513661/bitcoin-isnt-the-only-cryptocurrency-in-town/ MIT Technology Review: Bitcoin Isn't the only Cryptocurrency in Town]
*[http://ltc.blockr.io/documentation/api/ Litecoin Blockchain API]
*[http://www.vnbitcoin.org/litecoincalculator.php Litecoin Mining Calculator]

==See also==
[[Cryptocoin]]

[[Category:Alternative cryptocurrencies]]
[[Category:Digital currencies]]

Power Calc

2014-03-25T07:48:16Z

Dth123:

A site that will show the cost for electrical power to generate a 50 BTC block given a hash rate, power usage and cost of electricity as inputs.

* [[Difficulty]] field: BlockExplorer provides the [http://blockexplorer.com/q/getdifficulty current difficulty].
* Hash rate field: the value can determined from your [[:Category:Miners|miner]] client, or from the [[mining hardware comparison]].
* Power usage field: the value for a GPU card itself can be determined from the [[mining hardware comparison]]. More accurate values would come from a measurement such as that provided by a Kill-A-Watt device, for example.
* Cost of electricity: Because mining adds to your existing electrical consumption, the rate for mining is the cost of the next kWh, not necessarily your average cost per kWh. Your utility bill will provide the most accurate picture of what rate you'll be charged for additional consumption (your marginal electrical consumption rate).
** U.S. [http://www.eia.doe.gov/cneaf/electricity/epm/table5_6_a.html power costs per state]
** EU: [http://www.energy.eu/#Domestic domestic] [http://www.energy.eu/#Industrial industrial]

==Example==
A typical [[mining rig]] with a single ATI HD 5970 with the minimum components (PSU, mobo, HD, graphics card) will consume about 380W. At the difficulty level on April 9, 2011 (82347) using a modern miner that hash about 600MHash/S with that hardware, the cost of electricity to generate a block is $6.84 USD, using the typical U.S. residential rate (about $0.11/kWh).

Given that a block is 50 BTC and the BTC/USD market rate on that date was about $0.75 USD, then over 18% of the proceeds from mining went to pay the cost of electricity required to mine that block.

==See Also==

* [[TP's Bitcoin Calculator]]
* [[Generation Calculator]]
* [[Profitability Calculator]]
* [http://en.wikipedia.org/wiki/Electricity_pricing#Global_electricity_price_comparison Global electricity price comparison] on Wikipedia
* [http://www.bitcoinminer.com/post/2361900289 Where To Mine - Prices of Electricity]
* [http://www.bitcoinminer.com/post/2858427974 Time-of-use electric pricing irrelevant — Mining is 24x7]

==External Links==

* [[TP's Bitcoin Calculator]][http://tpbitcalc.appspot.com/]
* [http://lorelei.kaverit.org/cgi/calc.py Power Calc]
* [http://www.vnbitcoin.org/bitcoincalculator.php Vnbitcoin.org Bitcoin Mining Calculator]

[[Category:Mining]]
[[Category:Calculators]]

Vnbitcoin's Bitcoin Calculator

2014-03-25T07:44:27Z

Dth123: Created page with "[http://www.vnbitcoin.org/bitcoincalculator.php Vnbitcoin's Bitcoin Mining Calculator] is a bitcoin calculator to estimate bitcoin mining profitability and tool to find good r..."

[http://www.vnbitcoin.org/bitcoincalculator.php Vnbitcoin's Bitcoin Mining Calculator] is a bitcoin calculator to estimate bitcoin mining profitability and tool to find good return bitcoin miners to buy. Live calculator updates instantly with bitcoin network hashrate and exchange rate. Using hashrate difficulty from the last 4 increments to predict future bitcoin miners performances.

== See also ==
* [[Generation Calculator]]
* [[Profitability Calculator]]
* [[Power Calc]]

== External links ==
* [http://www.vnbitcoin.org/bitcoincalculator.php Vnbitcoin's Bitcoin Mining Calculator]

[[Category:Mining]]
[[Category:Websites]]
[[Category:Open Source]]
[[Category:Calculators]]
[[Category:Generation Calculator]]
[[Category:Profitability Calculator]]
[[Category:Power Calculator]]

Profitability Calculator

2014-03-25T07:37:42Z

Dth123:

Aids in estimating mining profits at current network and market conditions.

The current [[difficulty]] is obtained from [[Bitcoin Block Explorer]] and the USD exchange rate is taken from the highest bid on the [[Currency Exchange]] [[MtGox]].

== See also ==
* [[Generation Calculator]]
* [[Power Calc]]

==External Links==
* [https://cex.io/calc Bitcoin Profit Calculator - CEX.IO]
* [http://www.coinish.com/calc/ Coinish Mining Calculator]
* [http://btcserv.net/bitcoin-mining-calculator BTCServ Bitcoin Mining Calculator]
* [[TP's Bitcoin Calculator]][http://tpbitcalc.appspot.com/](useful for pool mining)
* [http://bitcoinX.com/profit/ BitcoinX.com Mining Profitability Calculator] - since 2011-04-14
* [http://0x10.org/sandbox/bitcalc/ Mining Break Even Calculator] (also useful for pool mining)
* [http://bitcoin.web-share.nl/ Easy BitCoin Mining Calculator] (also useful for pool mining)
* [http://btcsec.com/calculator/ Online Bitcoin Profitability Mining Calculator] (Russian)
* [http://blockchained.com/profit/ Blockchained.com Bitcoin Mining Profitability Calculator] - (with decline factor)
* [http://mining-profit.com/ Detailed Cloud Mining Profitability Calculator]
* [http://www.vnbitcoin.org/bitcoincalculator.php Vnbitcoin.org Bitcoin Mining Calculator]
[[Category:Mining]]
[[Category:Calculators]]

Generation Calculator

2014-03-25T07:36:11Z

Dth123:

Shows an estimate of the amount of time, on average, that you will need to do mining at the specified hash rate before you will generate a [[blocks|block]] and earn bitcoins. Additionally, the optimistic (50% probability) and pessimistic (95% probability) estimates are shown as well.

The hash rate refers to the rate that your mining hardware is performing at as reported by your miner software or from an estimate obtained from the [[mining hardware comparison]] tables.

The calculation is performed like this:
*Get the current [[target]].
*Divide by 115792089237316195423570985008687907853269984665640564039457584007913129639935, which is the maximum value of a 256-bit number. You now have the probability of a single hash solving a block.
*Take the reciprocal of the probability to get the average number of hashes to solve a block.
*Divide the average number of hashes by your hash/s (''not'' khash/s) to get the average number of seconds required to solve a block.

==See Also==

* [[TP's Bitcoin Calculator]]
* [[Power Calc]]
* [[Profitability Calculator]]

==External Links==
* [http://www.coinish.com/calc/ Coinish Mining Calculator]
* [[TP's Bitcoin Calculator]][http://tpbitcalc.appspot.com/]
* [http://www.alloscomp.com/bitcoin/calculator.php Generation Calculator]
* [http://btcsec.com/calculator/ BTCsec.com Online Calculator] (Russian)
* [http://www.vnbitcoin.org/bitcoincalculator.php Vnbitcoin.org Bitcoin Calculator]
[[Category:Mining]]
[[Category:Calculators]]