The electricity calculation to do before buying a miner
A simple worked example turns watts and your utility rate into a monthly operating estimate.
Start with watts at the wall
For an operating-cost estimate, use the power drawn by the complete setup, including its supply and cooling. A chip specification and a wall measurement need not be the same. Use the manufacturer's rated requirements for electrical compatibility; the calculation here is only an energy-cost example, not an instruction to modify wiring or equipment.
Work the numbers
Daily energy in kilowatt-hours equals watts divided by 1,000, multiplied by hours running. At 100 watts for 24 hours, that is 2.4 kWh per day. At an illustrative rate of $0.20 per kWh, energy costs $0.48 per day, or $14.40 over 30 days. Those are example inputs, not a claim about a particular miner or your utility bill.
Test an uncomfortable scenario
Repeat the calculation with a higher electricity rate and a lower payout. For example, the same 100-watt setup costs $21.60 over 30 days at $0.30 per kWh. If expected proceeds only barely cover the first scenario, a small change can erase the margin. Include pool or service fees separately, and avoid treating a brief high-payout period as a permanent baseline.
Keep purchase cost separate
An operating surplus is what remains after ongoing costs. Payback also has to cover the equipment purchase. A hypothetical $300 setup with a stable $10 monthly surplus would require 30 months to repay its price, before considering repairs or changing conditions. The word “stable” is doing important work: real payouts and costs can change. Record actual results instead of letting the original sales estimate become your accounting system.
References and method
Worked arithmetic using explicitly hypothetical inputs. These examples are not a product earnings estimate.