Electricity Cost Calculator
Estimate monthly and annual electricity cost from watts, operating hours, quantity and utility rate.
Estimate monthly and annual electricity cost from watts, operating hours, quantity and utility rate.
Estimate monthly and annual electricity cost from watts, operating hours, quantity and utility rate.
Enter your own equipment values. The calculator uses transparent assumptions so you can adjust efficiency, reserve and operating conditions.
Use Real Equipment Ratings
Estimate monthly and annual electricity cost from watts, operating hours, quantity and utility rate.
Calculator Guidance
Use the result for planning, then verify the exact product manual, nameplate ratings and operating limits.
Electricity Cost Calculator
Planning estimate only.
Formula
Monthly cost = watts ÷ 1000 × hours/day × days × quantity × rate per kWh.
Examples
| Load | Use | Rate | Monthly Cost |
|---|---|---|---|
| 100W | 8h/day | $0.18/kWh | $4.32 |
| 1500W | 2h/day | $0.18/kWh | $16.20 |
| 500W | 24h/day | $0.18/kWh | $64.80 |
Billing Limits
Tiered Rates
Utilities may charge multiple rates.
Time of Use
Prices change by hour.
Demand Charges
Some plans add peak demand.
Taxes and Fees
Not included.
Cycling Appliances
Use measured average energy.
Solar Credits
Net metering changes net cost.
How to Use the Result in the Real World
Treat the calculated result as a planning baseline rather than an exact promise. Real systems lose energy through conversion, wiring, temperature effects and internal electronics, while appliances can draw differently from their nameplate ratings.
Leave practical headroom instead of selecting equipment that exactly matches the result. Extra margin helps with startup surges, battery aging, changing weather and future loads, and it reduces the chance that normal variation pushes the system beyond its limits.
When the result affects a major purchase, verify the important inputs. Measure appliance consumption when possible, check the exact inverter or charge-controller limits, and compare the calculation with the equipment manufacturer's specifications.
Frequently Asked Questions
What is a kWh?
One kilowatt used for one hour.
Where do I find my rate?
On the utility bill; include delivery charges when appropriate.
Does this include fees?
No.
How do I handle cycling appliances?
Use measured kWh or average watts.
What about time-of-use rates?
Calculate each period separately.
Can this estimate generator cost?
No, fuel cost needs a different calculator.