Calculating electricity costs for Bitcoin mining: simple formula & examples

Before you run a Bitcoin miner around the clock, look at the electricity bill: power is by far the largest running cost of home mining. The calculation is simple, and for a small Bitaxe it comes to a few euros a month.

The formula

You need two values: your device’s power draw in watts and your electricity price per kilowatt-hour (kWh). Running 24/7, a month has around 730 hours.

Monthly cost ≈ (watts ÷ 1000) × 730 × electricity price per kWh

Example: a Bitaxe at 15 watts and 30 ct/kWh → (15 ÷ 1000) × 730 × €0.30 ≈ €3.29 per month. Over a year that is around €39.

Example values (at 30 ct/kWh)

• Bitaxe Gamma (~15 to 18 W): ~0.36 to 0.43 kWh/day → around €3.30 to €3.90 per month.
• Nerdaxe Gamma (~15 W): ~0.36 kWh/day → around €3.30 per month.
• NerdQaxe ++ (~80 W): ~1.9 kWh/day → around €17.50 per month.
• NerdOctaxe (~200 W): ~4.8 kWh/day → around €44 per month.

If your electricity price is higher or lower, the cost scales in proportion: at 40 ct/kWh multiply by 40/30, at 25 ct/kWh by 25/30.

Don’t forget the waste heat

A miner turns almost all the electricity it uses into heat. In winter it therefore covers part of your heating, and you save that share elsewhere. In summer the waste heat is a drawback, especially with the larger devices.

How to lower electricity costs

• Your own solar power: daytime surplus that would otherwise go to the grid for little or no payment costs you far less than grid power.
• Night or dynamic tariffs: mine in cheap time windows and pause during expensive ones.
• Efficiency tuning: a lower J/TH gets the same hashrate from fewer watts; see AxeOS tuning.
• Good cooling: cooler ASICs run more efficiently and more stably.

Putting electricity costs in perspective

Electricity costs alone do not tell you whether mining “is worth it”. You have to weigh them against the expected return, which is low for home mining. How to add up both realistically is shown in Calculating mining profitability realistically.

A small Bitaxe is an inexpensive hobby that costs about as much electricity per month as a coffee or two. With larger devices like the NerdOctaxe, your electricity price deserves a close look. The monthly cost of every device in one table, plus noise and heat, is on the home mining page.