Bitcoin Mining | How to Mine Bitcoins | How Much a Miner Earns | What Do I Need to Mine Bitcoins?

What Is Bitcoin Mining?

Chances are you hear the phrase “bitcoin mining” and your mind begins to wander to the Western fantasy of pickaxes, dirt, and striking it rich. As it turns out, that analogy isn’t too far off.

Bitcoin mining is performed by high-powered computers that solve complex computational math problems; these problems are so complex that they cannot be solved by hand and are complicated enough to tax even incredibly powerful computers.

What Is Bitcoin Mining?

Bitcoin mining is the process by which new bitcoins are entered into circulation, but it is also a critical component of the maintenance and development of the blockchain ledger. It is performed using very sophisticated computers that solve extremely complex computational math problems.

Cryptocurrency mining is painstaking, costly, and only sporadically rewarding. Nonetheless, mining has a magnetic appeal for many investors interested in cryptocurrency because of the fact that miners are rewarded for their work with crypto tokens. This may be because entrepreneurial types see mining as pennies from heaven, like California gold prospectors in 1849. And if you are technologically inclined, why not do it?

However, before you invest the time and equipment, read this explainer to see whether mining is really for you. We will focus primarily on Bitcoin (throughout, we'll use "Bitcoin" when referring to the network or the cryptocurrency as a concept, and "bitcoin" when we're referring to a quantity of individual tokens).

A New Gold Rush

The primary draw for many mining is the prospect of being rewarded with Bitcoin. That said, you certainly don't have to be a miner to own cryptocurrency tokens. You can also buy cryptocurrencies using fiat currency; you can trade it on an exchange like Bitstamp using another crypto (as an example, using Ethereum or NEO to buy Bitcoin); you even can earn it by shopping, publishing blog posts on platforms that pay users in cryptocurrency, or even set up interest-earning crypto accounts.

An example of a crypto blog platform is Steemit, which is kind of like Medium except that users can reward bloggers by paying them in a proprietary cryptocurrency called STEEM. STEEM can then be traded elsewhere for Bitcoin.

The Bitcoin reward that miners receive is an incentive that motivates people to assist in the primary purpose of mining: to legitimize and monitor Bitcoin transactions, ensuring their validity. Because these responsibilities are spread among many users all over the world, Bitcoin is a "decentralized" cryptocurrency, or one that does not rely on any central authority like a central bank or government to oversee its regulation.

Bitcoin Mining | How to Mine Bitcoins | How Much a Miner Earns | What Do I Need to Mine Bitcoins?


How to Mine Bitcoins

Miners are getting paid for their work as auditors. They are doing the work of verifying the legitimacy of Bitcoin transactions. This convention is meant to keep Bitcoin users honest and was conceived by Bitcoin's founder, Satoshi Nakamoto. By verifying transactions, miners are helping to prevent the "double-spending problem." 

Double spending is a scenario in which a Bitcoin owner illicitly spends the same bitcoin twice. With physical currency, this isn't an issue: once you hand someone a $20 bill to buy a bottle of vodka, you no longer have it, so there's no danger you could use that same $20 bill to buy lotto tickets next door. While there is the possibility of counterfeit cash being made, it is not exactly the same as literally spending the same dollar twice. With digital currency, however, as the Investopedia dictionary explains, "there is a risk that the holder could make a copy of the digital token and send it to a merchant or another party while retaining the original."

Let's say you had one legitimate $20 bill and one counterfeit of that same $20. If you were to try to spend both the real bill and the fake one, someone that took the trouble of looking at both of the bills' serial numbers would see that they were the same number, and thus one of them had to be false. What a Bitcoin miner does is analogous to that—they check transactions to make sure that users have not illegitimately tried to spend the same bitcoin twice. This isn't a perfect analogy—we'll explain in more detail below.

Once miners have verified 1 MB (megabyte) worth of Bitcoin transactions, known as a "block," those miners are eligible to be rewarded with a quantity of bitcoins (more about the bitcoin reward below as well). The 1 MB limit was set by Satoshi Nakamoto, and is a matter of controversy, as some miners believe the block size should be increased to accommodate more data, which would effectively mean that the bitcoin network could process and verify transactions more quickly.


Note that verifying 1 MB worth of transactions makes a coin miner eligible to earn bitcoin—not everyone who verifies transactions will get paid out.

1MB of transactions can theoretically be as small as one transaction (though this is not at all common) or several thousand. It depends on how much data the transactions take up.

"So after all that work of verifying transactions, I might still not get any bitcoin for it?"

That is correct. To earn bitcoins, you need to meet two conditions. One is a matter of effort; one is a matter of luck:

You have to verify ~1MB worth of transactions. This is the easy part.

You have to be the first miner to arrive at the right answer, or closest answer, to a numeric problem. This process is also known as proof of work.

"What do you mean, 'the right answer to a numeric problem'?"

The good news: No advanced math or computation is involved. You may have heard that miners are solving difficult mathematical problems—that's not exactly true. What they're actually doing is trying to be the first miner to come up with a 64-digit hexadecimal number (a "hash") that is less than or equal to the target hash. It's basically guesswork.

The bad news: It's guesswork, but with the total number of possible guesses for each of these problems being on the order of trillions, it's incredibly arduous work. In order to solve a problem first, miners need a lot of computing power. To mine successfully, you need to have a high "hash rate," which is measured in terms of megahashes per second (MH/s), gigahashes per second (GH/s), and terahashes per second (TH/s).

That is a great many hashes.

If you want to estimate how much bitcoin you could mine with your mining rig's hash rate, the site Cryptocompare offers a helpful calculator.

Mining and Bitcoin Circulation

In addition to lining the pockets of miners and supporting the Bitcoin ecosystem, mining serves another vital purpose: It is the only way to release new cryptocurrency into circulation. In other words, miners are basically "minting" currency. For example, as of Nov. 2020, there were around 18.5 million bitcoins in circulation.1

Aside from the coins minted via the genesis block (the very first block, which was created by founder Satoshi Nakamoto), every single one of those bitcoins came into being because of miners. In the absence of miners, Bitcoin as a network would still exist and be usable, but there would never be any additional bitcoin. There will eventually come a time when Bitcoin mining ends; per the Bitcoin Protocol, the total number of bitcoins will be capped at 21 million.2

However, because the rate of bitcoin "mined" is reduced over time, the final bitcoin won't be circulated until around the year 2140. This does not mean that transactions will cease to be verified. Miners will continue to verify transactions and will be paid in fees for doing so in order to keep the integrity of Bitcoin's network.

Aside from the short-term Bitcoin payoff, being a coin miner can give you "voting" power when changes are proposed in the Bitcoin network protocol. In other words, miners have a degree of influence on the decision-making process on such matters as forking.

How Much a Miner Earns

The rewards for Bitcoin mining are reduced by half every four years. When bitcoin was first mined in 2009, mining one block would earn you 50 BTC. In 2012, this was halved to 25 BTC. By 2016, this was halved again to 12.5 BTC. On May 11, 2020, the reward halved again to 6.25 BTC. In November of 2020, the price of Bitcoin was about $17,900 per bitcoin, which means you'd earn $111,875 (6.25 x 17,900) for completing a block.3 Not a bad incentive to solve that complex hash problem detailed above, it might seem.


If you want to keep track of precisely when these halvings will occur, you can consult the Bitcoin Clock, which updates this information in real-time. Interestingly, the market price of Bitcoin has, throughout its history, tended to correspond closely to the reduction of new coins entered into circulation. This lowering inflation rate increased scarcity and historically the price has risen with it.

If you are interested in seeing how many blocks have been mined thus far, there are several sites, including Blockchain.info, that will give you that information in real-time.

What Do I Need to Mine Bitcoins?

Although early on in Bitcoin's history individuals may have been able to compete for blocks with a regular at-home computer, this is no longer the case. The reason for this is that the difficulty of mining Bitcoin changes over time.

In order to ensure the smooth functioning of the blockchain and its ability to process and verify transactions, the Bitcoin network aims to have one block produced every 10 minutes or so. However, if there are one million mining rigs competing to solve the hash problem, they'll likely reach a solution faster than a scenario in which 10 mining rigs are working on the same problem. For that reason, Bitcoin is designed to evaluate and adjust the difficulty of mining every 2,016 blocks, or roughly every two weeks.

When there is more computing power collectively working to mine for bitcoins, the difficulty level of mining increases in order to keep block production at a stable rate. Less computing power means the difficulty level decreases. To get a sense of just how much computing power is involved, when Bitcoin launched in 2009 the initial difficulty level was one. As of Nov. 2019, it is more than 13 trillion.

All of this is to say that, in order to mine competitively, miners must now invest in powerful computer equipment like a GPU (graphics processing unit) or, more realistically, an application-specific integrated circuit (ASIC). These can run from $500 to the tens of thousands. Some miners—particularly Ethereum miners—buy individual graphics cards (GPUs) as a low-cost way to cobble together mining operations.

The photo below is a makeshift, homemade mining machine. The graphics cards are those rectangular blocks with whirring fans. Note the sandwich twist-ties holding the graphics cards to the metal pole. This is probably not the most efficient way to mine, and as you can guess, many miners are in it as much for the fun and challenge as for the money.

What Are Coin Mining Pools?

Mining rewards are paid to the miner who discovers a solution to the puzzle first, and the probability that a participant will be the one to discover the solution is equal to the portion of the total mining power on the network. 

Participants with a small percentage of the mining power stand a very small chance of discovering the next block on their own. For instance, a mining card that one could purchase for a couple of thousand dollars would represent less than 0.001% of the network's mining power. With such a small chance at finding the next block, it could be a long time before that miner finds a block, and the difficulty going up makes things even worse. The miner may never recoup their investment. The answer to this problem is mining pools. 

Mining pools are operated by third parties and coordinate groups of miners. By working together in a pool and sharing the payouts among all participants, miners can get a steady flow of bitcoin starting the day they activate their miners. Statistics on some of the mining pools can be seen on Blockchain.info.

"I've done the math. Forget mining. Is there a less onerous way to profit from cryptocurrencies?"

As mentioned above, the easiest way to acquire Bitcoin is to simply buy it on one of the many exchanges. Alternately, you can always leverage the "pickaxe strategy." This is based on the old saw that during the 1849 California gold rush, the smart investment was not to pan for gold, but rather to make the pickaxes used for mining.

To put it in modern terms, invest in the companies that manufacture those pickaxes. In a cryptocurrency context, the pickaxe equivalent would be a company that manufactures equipment used for Bitcoin mining. You may consider looking into companies that make ASICs equipment or GPUs instead, for example.

Is Bitcoin Mining Legal?

The legality of Bitcoin mining depends entirely on your geographic location. The concept of Bitcoin can threaten the dominance of fiat currencies and government control over the financial markets. For this reason, Bitcoin is completely illegal in certain places.

Bitcoin ownership and mining are legal in more countries than not. Some examples of places where it is illegal are Algeria, Egypt, Morocco, Bolivia, Ecuador, Nepal, and Pakistan.4 Overall, Bitcoin use and mining are legal across much of the globe.


Risks of Mining 

The risks of mining are often that of financial risk and a regulatory one. As mentioned, Bitcoin mining, and mining in general, is a financial risk. One could go through all the effort of purchasing hundreds or thousands of dollars worth of mining equipment only to have no return on their investment. That said, this risk can be mitigated by joining mining pools. If you are considering mining and live in an area that it is prohibited you should reconsider. It may also be a good idea to research your countries regulation and overall sentiment towards cryptocurrency before investing in mining equipment.

One additional potential risk from the growth of Bitcoin mining (and other proof-of-work systems as well) is the increasing energy usage required by the computer systems running the mining algorithms. While microchip efficiency has increased dramatically for ASIC chips, the growth of the network itself is outpacing technological progress. As a result, there are concerns about the environmental impact and carbon footprint of Bitcoin mining.

There are, however, efforts to mitigate this negative externality by seeking cleaner and green energy sources for mining operations (such as geothermal or solar), as well as utilizing carbon offset credits. Switching to less energy-intensive consensus mechanisms like proof-of-stake (PoS), which Ethereum is planning to do, is another strategy; however, PoS comes with its own set of drawbacks and inefficiencies.