MihsabaShare this free calculator
Send this tool to someone who needs the calculation.
How to use
Choose the first calculator to multiply a known kWh consumption by your price per kWh, with optional fixed charges and tax calculated on the subtotal. Or use the appliance calculator to convert watts and operating time into kWh. It returns daily, monthly and annual energy use and running cost for one or more appliances. If your electricity price is quoted in cents, divide by 100 before entering it: 20 cents/kWh means 0.20 currency units/kWh. For a tiered tariff, use the rate applicable to the appliance’s consumption. An average bill rate is useful for a rough estimate but may differ from the marginal cost of additional usage.
- Enter appliance power in watts.
- Set daily running hours and monthly running days.
- Enter appliance quantity and your actual price per kWh.
- Calculate to see energy and cost by period.
How it is calculated
Example
A 1,500 W appliance running 5 h/day for 30 days at 0.15 per kWh uses 7.5 kWh/day and 225 kWh/month, for an estimated monthly cost of 33.75.
Important notes
This estimates energy at the entered running power. Thermostatic or variable-load appliances may not draw rated power continuously. No country tariff tiers, taxes or fees are assumed; enter the effective per-kWh rate relevant to you.
Worked examples and interpreting results
A 1,500-watt appliance running four hours per day uses 6 kWh daily. This example assumes a hypothetical tariff of 0.20 currency units per kWh and a 30-day month.
| Case | Calculation | Result |
|---|---|---|
| Daily consumption | 1500 ÷ 1000 × 4 | 6 kWh |
| Monthly consumption | 6 × 30 | 180 kWh |
| Monthly cost at the assumed tariff | 180 × 0.20 | 36 |
How to check the result
Watts measure power; kWh measures energy consumed. Enter your actual tariff. Nameplate power can differ from average consumption when an appliance cycles, and this estimate excludes fixed charges and tiered pricing.
Two worked cases behind an electricity estimate
Worked case
An 800 W appliance used for 6 hours a day over 30 days consumes 144 kWh. At an illustrative rate of 0.18 per kWh, its energy charge is 25.92 currency units.
Compare another scenario
A 5 W standby load running all day for 30 days uses 3.6 kWh, equivalent to 0.648 currency units at the same hypothetical tariff.
How to interpret the result
Your actual bill can differ because of fixed service charges, tiered tariffs, taxes and the appliance duty cycle. Measured average draw is more reliable than rated wattage.
kWh price calculator: worked appliance examples
Divide watts by 1,000 to obtain kilowatts, multiply by running hours and quantity to obtain kWh, then multiply by the electricity price per kWh on your bill.
- 1000 W running 3 hours: (1000 ÷ 1000) × 3 = 3 kWh
- Cost at 0.20 per kWh: 3 × 0.20 = 0.60
- Cost over 30 equal days: 0.60 × 30 = 18.00
Important note
The energy-only estimate excludes standing charges and taxes. Actual consumption may differ from an appliance's rated wattage.
Related calculators
Frequently asked questions
How do I calculate an appliance electricity cost?
Convert watts to kW, multiply by running hours to get kWh, then multiply kWh by your electricity price per kWh.
How do watts become kWh?
Divide watts by 1,000 to get kW, then multiply by running hours.
Where do I get the kWh price?
Use your electricity bill or supplier tariff and enter the effective rate relevant to you.
Does this include tariff tiers or tax?
No. It is a generic calculator driven by the rate you enter.
How much does a 1,000-watt appliance cost to run for 8 hours?
At constant power it uses 8 kWh. At a hypothetical price of 0.20 currency units/kWh, that costs 1.60 per day or 48 for 30 days. Enter your own rate for your estimate.
Should I enter cents or currency units per kWh?
Enter the price in base currency units. For 20 cents per kWh, enter 0.20, not 20. A result of 1.60 then means 1.60 in that same currency.
How do I calculate appliance electricity cost from watts and hours?
Divide the rated watts by 1,000 to get kW. Multiply by hours of operation and number of devices to get kWh, then multiply by your tariff per kWh. A 1,500 W appliance used for two hours consumes 3 kWh; at 0.20 per kWh the energy cost is 0.60 in the tariff's currency.
How much does a 1 kW appliance cost to run for one hour?
One kilowatt operating at a constant power for one hour uses 1 kWh. Multiply 1 kWh by your billed unit price; if it is 0.25, the energy cost is 0.25. Daily or monthly costs depend on total running hours, and billing may also include taxes or fixed charges.