Quick electricity cost examples
| Example load | Use | Energy | Cost at $0.16/kWh |
|---|---|---|---|
| 10W LED light | 5h/day | 1.5kWh/month | $0.24/month |
| 60W laptop | 8h/day | 14.4kWh/month | $2.30/month |
| 100W television | 4h/day | 12kWh/month | $1.92/month |
| 1,500W space heater | 4h/day | 180kWh/month | $28.80/month |
These are calculation examples, not universal appliance ratings or electricity prices. Use measured average power and your own rate when possible.
How to calculate electricity cost
- Convert watts to kilowatts: kW = W ÷ 1,000.
- Calculate energy: kWh = kW × hours.
- Calculate cost: cost = kWh × electricity rate.
For example, a 1,500W device running 2 hours per day uses 1.5kW × 2h = 3kWh/day. At $0.16/kWh, it costs 3 × $0.16 = $0.48/day.
The monthly estimate uses the days-per-month value you enter. The yearly estimate uses daily kWh × 365, so changing the monthly day count does not distort the annual result.
Watts vs kWh
Watts and kilowatts measure power: the rate at which a device uses energy. Watt-hours and kilowatt-hours measure energy used over time. Your electricity price is normally an energy rate per kWh. Avoid describing a 1kW load as “1kW per hour”; if it runs for one hour, it uses 1kWh.
Already know the energy used? Select “Known energy use in kWh” to multiply that measured value directly by your rate.
How to find your electricity rate
Check your utility bill for the energy charge stated per kWh. Your effective price may include tiered rates, time-of-use pricing, taxes, delivery charges or fixed fees. This calculator multiplies energy by the single rate you enter; fixed monthly fees are not included.
Why actual appliance consumption can vary
Nameplate wattage may not equal average consumption. Refrigerators and air conditioners cycle, computers change load, heaters use thermostats, motors can have startup surges and many devices draw standby power. A plug-in energy meter or a device's measured kWh is usually more accurate than a nameplate-only estimate.
Electricity cost calculator FAQ
How do you calculate electricity cost?
Convert watts to kilowatts, multiply kilowatts by operating hours to get kWh, then multiply kWh by your electricity rate.
How much does it cost to run a 1,000 watt appliance?
A 1,000W appliance uses 1kWh each hour it runs. At a rate of $0.20 per kWh, that costs $0.20 per hour.
How do I calculate kWh from watts?
Divide watts by 1,000 to get kilowatts, then multiply by hours used. For example, 500W for 2 hours uses 1kWh.
How much does 1 kWh cost?
The cost of 1kWh is the electricity rate shown on your bill. Rates vary by utility, location, plan, time of use, taxes and fees.
How do I calculate monthly appliance running cost?
Multiply the appliance power in kW by hours used per day, days used per month and your cost per kWh.
Does appliance wattage equal actual electricity use?
Not always. Nameplate wattage can differ from average power because appliances may cycle, change load, use thermostats or draw standby power.
How do I find my electricity rate per kWh?
Check your utility bill for an energy charge stated per kWh. If your bill has tiered or time-of-use prices, use the rate that applies to the period you are estimating.