# Electricity cost calculator

> Enter an appliance's wattage, how many hours a day you run it, and your electricity rate to see exactly what it costs per day, month, and year.

Calculate how much an appliance or device costs to run. Enter wattage, hours per day, days, and your electricity rate.

**Interactive version:** https://onlinecalculator.me/everyday/electricity-cost/
**Category:** Everyday

## Formula

```
kWh per day = watts / 1,000 × hours per day
Total kWh   = kWh per day × days
Cost        = total kWh × rate per kWh
```

## Common appliance wattages

| Appliance | Typical watts |
|-----------|--------------|
| LED bulb | 9–12 W |
| Laptop | 45–65 W |
| Desktop PC + monitor | 150–300 W |
| Refrigerator | 100–200 W |
| Electric oven | 2,000–5,000 W |
| Space heater | 750–1,500 W |
| Air conditioner (window) | 500–1,500 W |
| Clothes dryer | 4,000–5,000 W |

## Frequently asked questions

### How is electricity cost calculated?

Cost = watts ÷ 1,000 × hours × days × rate per kWh. Power in kilowatts times hours gives kilowatt-hours (kWh), which is what your utility bills you for.

### Where do I find my electricity rate?

Look at your electricity bill for the rate in cents per kWh. The US average is about $0.13/kWh, but rates vary widely by state and provider.

### How much does it cost to run a 60-watt bulb for a month?

A 60W bulb running 8 hours a day for 30 days uses 14.4 kWh. At $0.13/kWh that's about $1.87/month.

### How do I convert watts to kilowatts?

Divide watts by 1,000. A 1,500W space heater is 1.5 kW.

### How do I share my calculation?

Click "Share with my numbers" to copy a URL that reopens with your exact inputs.

## Sources

- [Kilowatt-hour (electricity billing unit)](https://en.wikipedia.org/wiki/Kilowatt-hour) — Wikipedia
- [Electricity explained](https://www.eia.gov/energyexplained/electricity/) — U.S. Energy Information Administration

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