Don't know today's hashprice? Derive it.
Hashprice is just the network's daily issuance value spread across all the hashrate competing for it. Fill these in and it writes the field above for you.
Revenue decay and cumulative cash flow
Power cost is flat. Revenue is not: each month the network grows, your share of it shrinks, and the gap narrows. The row where cumulative net crosses your hardware cost is the real payback — the row where monthly net turns negative is the day the machine becomes a space heater.
| Month | Hashprice | Revenue | Power | Net | Cumulative |
|---|
The two numbers that decide whether you keep it plugged in
Payback is an investment question you answer once. The hashprice floor and the breakeven power price are operating questions you answer every week of a bear market. Compare a machine against simply buying the coin with the mining profitability calculator, watch the next supply cut with the halving countdown, and check what fee pressure is doing to block revenue on the network fees page.
Why difficulty decay is the whole story
Take a 270 TH/s machine at 13.5 J/TH, five-cent power and a $42/PH/day hashprice. At 97% uptime it grosses $11.00 a day, burns $4.24 in electricity, and clears $6.59 after a 1.5% pool fee. A naive calculator divides $4,500 of hardware by $6.59 and reports 22.5 months. That number is wrong in a specific, predictable direction, because it assumes the machine's daily earnings in month 27 are identical to month one. They are not. The Bitcoin network retargets difficulty every 2,016 blocks to hold block time at ten minutes, so when new machines plug in, everyone's share of the same fixed issuance gets smaller. Hashrate has compounded through every cycle of the network's history. At a modest 1.5% monthly growth, revenue is down 16% after a year and 30% after two — while the power bill has not moved a cent.
That asymmetry is why the payback row in the table above lands materially later than the naive figure, and why in marginal configurations it never lands at all. Once the decayed hashprice crosses your floor, monthly net goes negative and the cumulative line starts falling again. There is no amount of patience that fixes a machine past that point; the only levers are cheaper power, a higher coin price, or a hashprice recovery driven by fees. This is precisely the mechanism that turns older-generation hardware into scrap after each halving, and it is entirely absent from every free calculator that quotes ROI in days.
The two numbers worth writing down are the hashprice floor and the breakeven electricity price. The floor is where revenue after pool fees exactly equals your power bill; on the example above it sits near $16.45/PH/day, meaning the machine tolerates a 61% hashprice collapse before it stops paying for its own electricity. The breakeven power price of about $0.128/kWh says the same thing from the other side: this configuration survives on industrial power and dies on retail. Sunk hardware cost is irrelevant to both. A miner deciding whether to run through a drawdown should ignore what the ASIC cost and look only at whether today's hashprice is above the floor — everything else is an accounting story about money already spent.