Electricity costs: the kWh math that dominates mining
Power is almost always the largest operating cost of mining. The math is one multiplication — watts to kilowatts, times hours, times your rate — and it belongs in your head before any profitability calculator.
Power vs energy — the one distinction
Power (watts) is the instantaneous rate your rig draws. Energy (kilowatt-hours, kWh) is power sustained over time — that is what the bill prices. A 3,000 W rig running one hour consumes 3 kWh. Saying '3,000 W per day' mixes the two and quietly breaks every estimate downstream.
The daily math
Daily cost = (watts ÷ 1,000) × 24 × rate. A 3 kW rig at $0.10/kWh: 3 × 24 × 0.10 = $7.20/day — $216/month, $2,628/year. At $0.15/kWh the same rig costs $10.80/day: the tariff, not the miner, decides whether mining is profitable.
Add the rest of the site honestly: cooling fans, pumps, and network gear can add 5–15% on top of miner-only draw (see the cooling lesson).
Find your real rate
Do not google 'average electricity price' — read one of your own invoices and compute the effective rate: total bill ÷ total kWh. That single number already includes fixed fees and taxes, which is the honest basis for mining math. The next lesson dissects what the bill actually contains.
See it live on pow.family
The electricity calculator under Tools runs this math with uptime and two-tariff comparison — pair it with a project page's live price to see if a coin clears your cost floor.