Before buying a Bitcoin miner, calculate its electricity cost from its actual wall-power draw, planned operating hours, and your local all-in electricity rate per kWh. This turns a hardware specification into a practical operating-cost estimate and avoids treating hashrate or an advertised energy rate as the full cost of running the machine.
The One Question to Answer Before You Buy: What Will This Miner Cost to Run?
The pre-purchase question is not simply whether a miner is efficient. It is: “What will this specific machine cost to power at my location and operating schedule?” Two operators can run identical hardware and face very different Bitcoin miner operating costs because their utility rates, billing structures, cooling needs, and uptime differ.
Start with a cost estimate before comparing projected earnings. A low purchase price does not compensate for a power draw that is poorly matched to your electricity rate. Conversely, a higher-efficiency machine may still be unsuitable if a site has expensive peak-period pricing or demand charges beyond energy use.
Understand Watts, Kilowatts, and Kilowatthours
A watt (W) measures power: the rate at which a device uses electricity. A kilowatt (kW) is 1,000 watts. A 3,500 W ASIC, for example, has a rated power draw of 3.5 kW.
A kilowatthour (kWh) measures energy used over time. Utilities generally bill energy consumption in kWh. If a 3.5 kW machine runs for one hour, it consumes 3.5 kWh. If it runs for 24 hours, it consumes 84 kWh.
This distinction matters when reviewing ASIC power consumption. The watt figure on a datasheet is not the daily charge. It becomes a cost only after you multiply it by runtime and your all-in rate per kWh.
The Electricity Cost Formula for a Bitcoin Miner
For a kWh-based estimate of Bitcoin mining electricity cost, use this formula:
Electricity cost = (miner power in W / 1,000) × operating hours × all-in electricity rate per kWh
You can also calculate energy use first:
- Miner power in kW = watts / 1,000
- Energy use in kWh = miner power in kW × operating hours
- Electricity cost = energy use in kWh × all-in rate per kWh
The formula estimates variable energy charges, not every possible item on a utility bill. It is still the right first calculation because it makes the largest operating input visible and lets you compare machines using the same local rate and planned hours.
Step 1: Find the Miner’s Real Wall-Power Specification
Use the miner’s stated wall-power consumption at the relevant voltage and operating condition. The manufacturer’s current datasheet is usually the best source because it should identify the model, rated power, input voltage, and test conditions.
Do not substitute hashrate or efficiency alone for power draw. Efficiency can help compare machines, but it does not reveal the actual kW load without the miner’s hashrate and operating mode. Consumption can also vary with firmware, ambient temperature, fan activity, power setting, overclocking, and production batch.
For planning, record:
- Rated wall power in W
- Required input voltage and electrical configuration
- Intended performance mode or firmware setting
- Whether the figure includes the power supply
- The source and date of the specification
If you are evaluating more than one machine, calculate each one separately. This makes it easier to see whether a lower ASIC power consumption figure produces a meaningful reduction at your site.
Step 2: Find Your All-In Electricity Rate per kWh
Your mining electricity rate per kWh should come from the applicable utility tariff or recent bills, not from an energy-only advertisement. The effective variable rate may include supply, delivery, taxes, riders, and other charges that rise with consumption.
What an all-in rate can include
Review the bill line by line. Charges expressed per kWh should be included in a variable-cost estimate. Keep fixed monthly charges separate unless you are explicitly estimating a full monthly bill. Commercial customers may also face demand charges based on peak kW, which a simple kWh formula does not capture.
Local tariffs control the actual numbers, and billing terminology can vary by market.
When time-of-use pricing changes the estimate
With time-of-use electricity rates, the effective price depends on when the miner runs. A 24/7 machine may consume power across off-peak, mid-peak, and peak periods. Calculate each period separately if rates differ materially, then add the results.
For example, a 3.5 kW miner running 20 off-peak hours at $0.08 per kWh and four peak hours at $0.16 per kWh would use 70 kWh off-peak and 14 kWh during peak hours. Its daily energy charge would be $5.60 + $2.24, or $7.84. If you plan to curtail during expensive periods, use the scheduled hours for each period rather than assuming continuous operation.
Step 3: Calculate Daily, Monthly, and Annual Electricity Cost
For a 24/7 operating estimate, multiply the miner’s kW load by 24 to find daily kWh. Then multiply daily kWh by the all-in rate.
For monthly use, use the number of operating days you actually expect in that billing period. Do not assume every month is exactly 30 or 31 days. Planned shutdowns, maintenance windows, or curtailment programs change the result.
A practical workflow is:
- Calculate daily kWh from rated kW × planned daily hours.
- Multiply by your all-in rate to estimate daily energy charges.
- Multiply daily kWh and daily cost by the planned operating days in the billing period.
- Add separate fixed, demand-based, or facility costs where relevant.
- Repeat the calculation for a lower-uptime or higher-rate scenario.
Annual estimates are useful for hardware comparisons, but they should be treated as scenarios. Electricity tariffs, runtime, and equipment conditions can change.
Worked Example: Estimating the Electricity Cost of a 3,500 W Miner
Illustrative example only: A 3,500 W miner is 3.5 kW. If it operates for 24 hours, its energy use is:
3.5 kW × 24 hours = 84 kWh per day
At an illustrative all-in rate of $0.10 per kWh, the energy charge is:
84 kWh × $0.10 = $8.40 per day
This example does not represent a particular miner model, a current market electricity price, or a guaranteed Bitcoin miner operating cost. It excludes fixed bill components, demand charges, and power used by cooling or other site equipment.
For a 28-day billing period at the same illustrative usage and rate, the energy charge would be $235.20. For a 31-day period, it would be $260.40. The difference is why monthly estimates should use the intended number of operating days.
Costs a Simple kWh Calculation Can Miss
A miner’s wall power is not always the same as total facility power. The basic formula is still useful, but it may understate total electricity cost when other equipment is needed to keep the ASIC running reliably.
Facility overhead
Add site overhead where applicable, including fans, ventilation, cooling, power-distribution losses, networking equipment, and other supporting loads. In a larger operation, these loads can be measured separately or represented through a documented facility-power assumption. Keep ASIC wall power and total facility power distinct so the estimate remains transparent.
Fixed and demand-based utility charges
Some tariffs include fixed monthly fees. Commercial and industrial tariffs may also include demand charges based on the highest measured kW over a billing period. A miner that runs continuously can affect that peak. Review the tariff rather than assuming that multiplying kWh by a single rate captures the entire bill.
Use Electricity Cost With, Not Instead of, a Mining Revenue Estimate
Electricity cost is a core input to a mining decision, but it is only one input. Hardware price, uptime, pool fees, Bitcoin price, network difficulty, transaction fees, and payout method can all change the result.
After calculating electricity cost locally, you can use the ViaBTC Profit Calculator as a separate earnings scenario. The estimate is for reference; actual rewards can differ with payment method, difficulty changes, miner fees, and pool luck.
Keep the two calculations separate: first estimate the cost to power the machine, then compare it with a clearly labelled revenue scenario. That approach is more useful than treating a single projected profit number as a purchase decision.
Pre-Purchase Electricity Cost Checklist
Before committing to a miner, verify these points:
- Confirm wall-power consumption, voltage, and test conditions in the manufacturer’s current datasheet.
- Use your applicable all-in electricity rate per kWh, not only an advertised supply rate.
- Calculate daily use from planned operating hours and monthly use from planned operating days.
- Model time-of-use periods if your tariff has different rates by time.
- Identify fixed charges and demand charges that sit outside a simple kWh calculation.
- Include cooling, ventilation, and distribution losses when estimating facility power.
- Test a range of uptime and tariff scenarios before comparing revenue estimates.
The most reliable electricity cost estimate is not the most complicated one. It is built from the real wall-power specification, the correct local tariff, and a clearly stated operating plan. Calculate that baseline before buying hardware, then revisit it whenever your utility rate, equipment settings, or site conditions change.