Category
Tech
Power Cost Calculator
Estimate monthly kWh usage and electricity cost from device wattage and runtime
Estimated time
1 min
Usage and Rate Inputs
Enter device power draw, runtime, and electricity rate to estimate monthly and annual energy cost.
Enter the typical power use of the device or full setup in watts. Use measured values when possible.
Average number of hours the device runs each day during active usage days.
Number of days this device runs in a typical month. Use 30 for every-day usage.
Use the energy charge from your utility bill in dollars per kilowatt-hour.
Power presets
Hours/day presets
Rate presets
Formula Summary
Power in kW = power draw in watts / 1,000
Daily energy (kWh) = power in kW x hours per day
Monthly kWh = daily energy x days per month
Monthly cost = monthly kWh x electricity rate ($/kWh)
Annual cost = monthly cost x 12
How It Works
This calculator estimates electricity cost from power draw, daily usage time, monthly usage days, and your utility rate per kWh.
It converts watts to kilowatts first, then calculates monthly energy use and multiplies by your electricity rate.
- Convert power draw to kilowatts: kW = watts / 1,000.
- Daily kWh = kW x hours per day.
- Monthly kWh = daily kWh x days per month.
- Monthly cost = monthly kWh x electricity rate ($/kWh).
- Annual cost = monthly cost x 12.
Example Calculations
Gaming desktop setup
Power: 450 W, 6 hours/day, 30 days/month, rate: $0.16/kWh
Monthly kWh: 81.00, Monthly cost: $12.96, Annual cost: $155.52
Space heater usage
Power: 1,500 W, 4 hours/day, 30 days/month, rate: $0.18/kWh
Monthly kWh: 180.00, Monthly cost: $32.40, Annual cost: $388.80
Always-on network gear
Power: 120 W, 24 hours/day, 30 days/month, rate: $0.14/kWh
Monthly kWh: 86.40, Monthly cost: $12.10, Annual cost: $145.15
Frequently Asked Questions
What does kWh mean?
kWh (kilowatt-hour) is an energy unit on your electric bill. A 1,000 W device running for 1 hour uses 1 kWh.
Should I enter device max wattage or typical wattage?
Typical measured wattage gives the most realistic estimate. Use max wattage for worst-case planning or safety margin.
Why use days per month instead of fixed 30?
Some setups only run on workdays or selected days. Entering actual usage days gives a more accurate monthly estimate.
Does this include utility delivery fees and taxes?
No. It estimates energy charge only from $/kWh. Add fixed fees, taxes, and demand charges separately if your bill includes them.
Related Calculators
Download / Upload Time Calculator
Estimate transfer time from file size, speed, and real-world network efficiency
Storage Calculator
Estimate storage for photos, videos, and documents with format presets and backup copies
Cloud Egress Cost Calculator
Estimate monthly cloud data transfer cost with rate per GB and optional tiered pricing