Guide · Oct 26, 2026 · 5 min read
How to use a bitcoin mining profitability calculator: the four numbers it needs
A mining calculator asks for four numbers and does one subtraction: what the machine earns in a day, minus what its electricity costs. Get the four right and the answer is trustworthy. Get one wrong, and the result looks precise while being fiction. Here is where each number comes from.
TL;DR
- Four numbers go in: the hashrate the machine really runs, its power at the wall, your price per kilowatt-hour and the pool's fee.
- The calculator supplies the rest: bitcoin's price and the network's difficulty, which together set what a petahash earns in a day.
- The answer is a day, not a promise. Run it at your real rate, and again at the rate you hope for, so you see both.
- Break-even rate is the number to keep: the power price at which the machine earns exactly what it burns.
A calculator is one subtraction with two sides
Every profitability calculator, whoever built it, does the same thing. It works out what your machine earns in a day, works out what its electricity costs in a day, and shows you the difference. Everything else on the page is decoration or a way of asking you for the inputs.
The earnings side depends on two things you control, your machine's hashrate and the pool's fee, and two you do not, bitcoin's price and the network's difficulty. The cost side depends on how much power the machine pulls and what you pay for it. That makes four numbers from you and two from the world. Most bad results come from getting one of your four wrong, so we take them in turn.
If any word here is new, the guides to what a hash is and how to read a spec sheet cover the vocabulary.
Number one: the hashrate the machine really runs
The calculator asks for hashrate in terahashes per second. The easy answer is the figure on the spec sheet, and it is usually the right place to start. For the Antminer S21 XP in our store that is 270 TH/s.
The machine on your rack rarely reads exactly that. A pool shows the hashrate it receives from you over time, and it wanders from minute to minute, so a day's average is the honest figure. Our guide to why a miner's hashrate reads lower than its spec sheet explains why. If a calculator lets you type a number, type the average you see on the pool, or the spec figure less a few per cent, and not the best reading of the week.
Number two: the power it pulls at the wall
The second input is watts, the electricity the machine draws while it hashes. Take it from the spec sheet again, and remember that it is the power at the wall, not the power of the chips. The same S21 XP draws 3,645 W, which is 13.5 joules for every terahash it computes.
Watts become money in two steps. A machine drawing 3,645 W for 24 hours uses 3.645 kilowatts times 24, or 87.48 kilowatt-hours a day. Our guide to how much electricity a miner uses goes through that sum with a different machine if you want a second worked example.
A water-cooled or immersion machine has a few extra pumps and fans to run. Some calculators ask for that overhead separately, and if yours does not, a hosting quote that says what it includes is worth more than a guess.
Number three: your price per kilowatt-hour, not a typical one
This is the input that moves the answer most, and it is the one people fill in from habit. Many calculators start with a default rate that is a round number and nothing to do with you. Replace it with the rate you will actually be billed, per kilowatt-hour, with every fee in it.
Our hosted sites show how far the answer moves with the rate: 3.9¢ in Nigeria, 6¢ in Argentina and the UAE, from our site page. Run the same machine at both and the daily margin changes by about 40%, which is why where a machine lives is a bigger decision than which brand it is. The break-even electricity chart draws the same idea for every class of machine.
Number four: the pool's fee
A pool keeps a small percentage of what your machine earns for its work of combining many machines into steady payouts. A calculator asks for it as a percentage, and the number is on the pool's own page. Type that one, and not zero.
Pools also differ in how they pay and in the smallest amount they will send, which a calculator cannot show you. Our guides to what a mining pool is and how pools pay you cover both. For a feel for the size of the fee: a pool that kept 2%, as a made-up example, would take about 20¢ a day from the machine in the next section.
What the calculator fills in for you: price and difficulty
Two inputs are not yours. Bitcoin's price says what each coin is worth, and the network's difficulty says how many coins a given amount of hashrate wins. A good calculator reads both from live data and combines them into one figure, hashprice: what one petahash, which is 1,000 terahashes, earns in a day. It was $36.27 on 25 October 2026 on our hashprice chart, and the guide to what hashprice is shows how it is built.
If a calculator makes you type the bitcoin price and difficulty yourself, check them against a dated source and write the date next to your answer. Difficulty adjusts about every two weeks, and a higher difficulty means the same hashrate wins fewer coins. The guide to difficulty explains the adjustment.
A worked example, line by line
Take the S21 XP: 270 TH/s, which is 0.27 petahash, drawing 3,645 W. At $36.27 a petahash a day it earns 0.27 times $36.27, or $9.79 a day. Its electricity is 87.48 kilowatt-hours a day. At 6¢ that costs $5.25, leaving $4.54. At 3.9¢ it costs $3.41, leaving $6.38.
The most useful number to pull out of a calculator is the break-even rate: the power price at which the day's earnings exactly equal the day's electricity. Here that is $36.27 divided by the 324 kilowatt-hours a petahash uses in a day at 13.5 J/TH, which is 11.2¢. Anywhere your power costs less than that, the machine pays its own bill today. The cheaper your power sits below it, the bigger the margin.
Now see what a wrong input does. If the machine really runs 5% under its spec sheet, the earnings are $9.30 instead of $9.79, and the 6¢ margin drops from $4.54 to $4.05. A small error in one input is a 10% error in the answer.
Earned minus burned, per day. Everything else is checking that both halves are honest.
| One day, Antminer S21 XP | At 6¢ | At 3.9¢ |
|---|---|---|
| Earned: 0.27 PH × $36.27 | $9.79 | $9.79 |
| Electricity: 87.48 kWh | $5.25 | $3.41 |
| Left over per day | $4.54 | $6.38 |
| Break-even power price | 11.2¢ | 11.2¢ |
What the answer tells you, and what it does not
A calculator answers one question: at today's price and difficulty, does this machine earn more than it burns? It does not know where bitcoin goes next or whether difficulty rises, so treat its output as a snapshot with the date on it, and not as a forecast. Output is not guaranteed.
It also leaves out the machine's price. Our guides to what a miner costs all-in and how long a miner takes to pay for itself add that step. The per-machine figures on our own pages, such as the S21 XP, put it all in one place.
The last check is the one that matters for someone who plans to keep what they mine. Run the calculator in coins, not dollars. The cost of making one bitcoin is the electricity bill divided by the coins mined, whatever the market price is on the day. On 26 October 2026 our best case, the Antminer S23 XP Hyd at 3.9¢ in Nigeria, made a coin for about $18,551 of electricity against a market price of $79,765, counting electricity only and not the machine or the pool fee. That gap, repeated every day, is what a miner who keeps the coins is collecting. The guide to why nobody sells the coins to pay the power bill explains the model.
Disclosure
Firsthand Bitcoin sells and hosts mining hardware, including this machine. No manufacturer, distributor or affiliate programme paid for or reviewed this page and we take no commission on the links above. Historical figures are computed from daily bitcoin price and network hashprice, each day valued at its own prices. Nothing here is investment advice.