A mining calculator makes one calculation and then stretches it. The daily figure is a snapshot of today. The yearly figure is that snapshot multiplied by 365, which quietly assumes difficulty, price and the block subsidy all stand still for a year. They do not. In the worked example below, the flat yearly figure is $1,226.40. Add difficulty growth of 3.5% a month and the same machine earns about $483 in its first year, and slips into loss in month 11.
Four numbers, four different promises
Open any mining profitability calculator and you get four answers at once: a daily profit, a weekly profit, a monthly profit and a yearly profit. They look like four measurements. They are one measurement, repeated at four lengths.
In my home mining checklist on this site, we settled the inputs: wall power instead of nameplate power, your marginal electricity price, the pool fee, a realistic uptime. This article is about the other side of the screen. Once the inputs are honest, the outputs still need reading, because each period figure carries a different promise, and only the shortest one comes close to keeping it.
The daily figure is roughly a measurement. It prices your hashrate against today’s network difficulty, today’s Bitcoin price and the current block subsidy, then subtracts your power cost and pool fee. If your inputs are right, today’s profit really is close to that number.
The weekly and monthly figures are the daily figure wearing a longer coat. And the yearly figure is where the trouble starts, because a year is long enough for every frozen assumption inside it to thaw.
What each period figure actually assumes
| Figure | How it is built | What it silently assumes |
| Daily profit | Today’s difficulty, price and subsidy, minus power cost and pool fee | Today is a normal day, and the machine ran all of it |
| Weekly profit | Daily figure times 7 | No difficulty adjustment lands inside the week |
| Monthly profit | Daily figure times 30 | Difficulty and price hold steady for a full month |
| Yearly profit | Daily figure times 365 | Nothing changes for a year: no difficulty growth, no price move, no halving |
Difficulty is the assumption that breaks first. Bitcoin retargets difficulty every 2,016 blocks, roughly every two weeks, to hold block times near ten minutes. When more hashrate joins the network, difficulty rises, and the same machine earns a smaller share of the same reward. The Cambridge Bitcoin Electricity Consumption Index exists largely to track this growth: the network’s power use climbs because the hashrate behind it climbs, year after year.
A weekly figure can survive one quiet adjustment. A yearly figure has to survive about twenty-six of them, plus whatever the price does, plus, for any machine bought now, the April 2028 halving. Multiplying one good day by 365 is not a forecast. It is the day, photocopied.
The worked example: one machine, three first years
Take the same illustrative machine from the checklist. It hashes at 200 TH/s, draws 3,500 W at the wall (3,500 divided by 200 is 17.5 J/TH), and uses 84 kWh a day. Electricity costs $0.10 per kWh. Gross revenue at today’s difficulty and price is $12.00 a day. The pool takes 2%, leaving net revenue of $11.76. Power costs $8.40 a day. Daily profit: $3.36.
Now read that machine’s first year three ways.
| Difficulty growth | Month 1 | Month 6 | Month 12 | First-year total |
| None (flat, the default view) | $100.80 | $100.80 | $100.80 | $1,226.40 |
| 2.5% a month | $100.80 | $58.85 | $15.04 | about $673 |
| 3.5% a month | $100.80 | $43.23 | -$13.59 | about $483 |
Monthly figures use 30-day months; the flat total is $3.36 times 365. At 3.5% monthly growth the machine slips below break-even in month 11, losing $4.94 that month. Treat the two growth rates as scenarios, not predictions: network difficulty has recently been growing at roughly 3 to 4% a month, so both sit inside the plausible range.
One detail does the damage. Your electricity cost does not decay. The machine burns the same 84 kWh and owes the same $8.40 every day of the year, whether difficulty moved or not. Revenue is the only side of the margin that shrinks, so the margin compresses from one side only. That is why month 12 at 3.5% growth is not a smaller profit but a loss: the revenue line crossed the cost line, and the cost line never moved.
This is also why the electricity price deserves its reputation as the number that decides home mining. At $0.10 per kWh the example survives most of the year even in the hard scenario. The U.S. Energy Information Administration puts the average U.S. residential price near 18 cents per kWh, and at that price this machine loses money from day one at today’s revenue. The calculator’s job is to show you that before the box arrives, not after.
Three smaller corrections to apply to any period figure
Uptime. Most calculators let you set an uptime figure, and it applies to revenue. Run the example at a realistic 95% instead of a perfect 100% and daily profit falls from $3.36 to about $2.77, before difficulty has moved at all. A machine that reboots, throttles in summer heat or sits idle during a pool outage does not earn the snapshot figure.
Pool payout scheme. The checklist covered FPPS and PPLNS in detail, so one sentence here: FPPS pays close to the expected value a calculator assumes, while PPLNS wanders above and below it from week to week. A single good week on PPLNS is luck, not a new daily rate, and annualising it repeats the original mistake at a smaller scale.
The halving. In April 2028 the block subsidy halves again, from 3.125 to 1.5625 BTC. Any monthly figure, yearly figure or payback period that crosses that date has to be split in two and priced separately on each side of it. In the worked example, halved net revenue is about $5.88 a day against the same $8.40 power cost: a loss of $2.52 a day at unchanged price and difficulty. The price may rise and rescue the machine. It may not. A yearly figure that steps over the halving without blinking is not optimistic or pessimistic. It is unfinished.
How to get a yearly figure you can defend
Three habits fix most of the damage.
First, never quote one yearly number. Run the calculation at zero difficulty growth, then at 2.5%, then at 3.5%, and quote the range. “Somewhere between $480 and $1,230 in year one, depending on how fast the network grows” is a less exciting sentence than “$1,226.40”, and it has the advantage of being defensible.
Second, give the figure a shelf life. Re-run it after each difficulty adjustment, roughly every two weeks. A yearly estimate made in January is a historical document by March.
Third, compute payback from the adjusted curve, not from month one. Payback is the month where the running total of monthly profits crosses the machine’s purchase price. On the flat view that crossing comes far too early, because the flat view assumes month twelve pays like month one.
Put a price on it and the gap stops being abstract. Say the machine costs $1,000. On the flat view, cumulative profit crosses $1,000 during month ten, and the purchase looks safe. At 2.5% monthly difficulty growth, the same machine earns about $673 across its whole first year and does not pay back at all. At 3.5%, it earns about $483. Nothing about the machine changed. Only the reading did.
The free mining profitability calculator at Bitcoin Calculator Tools has a monthly difficulty increase field built for exactly this. Set it to 2.5% or 3.5% and it projects twelve months of difficulty-adjusted profit, using live network difficulty from mempool.space, instead of one flat line. Whichever calculator you use, find that field. If it does not have one, the yearly figure it shows you is the photocopy, and you now know how to correct it by hand.
Two questions readers ask
Which figure should I trust? The daily figure, for running decisions: it tells you whether the machine earns more than it costs today. For a buying decision, trust only a difficulty-adjusted yearly range. Trust the flat yearly figure for nothing.
Does difficulty always rise? No. It falls when miners switch off in large numbers, and it has dropped for months at a stretch in the past. That cuts both ways: a falling-difficulty year would beat every scenario in the table above. Scenarios are not forecasts. They are a way of asking what happens to your money if the recent pattern continues, and of noticing that the honest answer is a range, not a point.
A calculator is not lying when it shows you a yearly profit. It is answering the question you asked, with the assumptions you left at their defaults. Ask the harder question, with difficulty growth switched on, and the same tool will tell you something much closer to the truth.
This article is educational and is not financial advice.
Sources of Information
- Cambridge Centre for Alternative Finance, Cambridge Bitcoin Electricity Consumption Index: https://ccaf.io/cbnsi/cbeci
- S. Energy Information Administration, Electric Power Monthly Table 5.6.A (average retail electricity price by state and sector), official source: https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a
