Electricity Cost Calculator
Find out how much any appliance costs to run per hour, day, month, and year. Pick a common appliance or enter custom wattage.
How to Calculate Electricity Cost
Every electrical appliance has a wattage rating that tells you how much power it draws. To figure out what it costs to run, you need three numbers: watts, hours of use, and your electricity rate.
Daily Cost = (Watts × Hours per Day ÷ 1,000) × Rate per kWh
Dividing by 1,000 converts watts to kilowatts, since electricity is billed in kilowatt-hours (kWh).
Where to Find Your Electricity Rate
Your rate per kWh appears on your monthly utility bill, usually listed as "energy charge" or "delivery charge." In the US, the national average is about $0.16/kWh, but it ranges widely — from around $0.10/kWh in states like Idaho and Louisiana to over $0.35/kWh in Hawaii and parts of New England. Our calculator auto-detects a typical rate for your country, but entering your actual rate gives the most accurate results.
Typical Appliance Running Costs
| Appliance | Watts | Typical Use | Annual Cost* |
|---|---|---|---|
| LED Light Bulb | 10W | 8 hrs/day | $4.67 |
| Laptop | 65W | 8 hrs/day | $30.37 |
| Refrigerator | 150W | 24 hrs/day | $210.24 |
| TV (55") | 100W | 5 hrs/day | $29.20 |
| Gaming PC | 500W | 4 hrs/day | $116.80 |
| Space Heater | 1,500W | 8 hrs/day | $700.80 |
| Central AC | 3,500W | 8 hrs/day | $1,635.20 |
| EV Charger (L2) | 7,200W | 3 hrs/day | $1,261.44 |
*Based on US average of $0.16/kWh. Your actual costs depend on your local rate.
Tips to Reduce Electricity Costs
The fastest wins are switching to LED lighting (saves 75% vs incandescent), using a smart thermostat (saves 10–15% on heating/cooling), and running large appliances during off-peak hours if your utility offers time-of-use pricing. Unplugging chargers and standby devices — often called "vampire power" — can save $100–$200 per year for an average household.
Frequently Asked Questions
Multiply watts by hours of daily use, divide by 1,000 to get kWh, then multiply by your rate per kWh. For example: a 100W TV used 5 hours a day at $0.16/kWh costs (100 × 5 ÷ 1,000) × $0.16 = $0.08 per day, or about $2.43 per month.
HVAC (heating and cooling) typically accounts for 40–50% of a home's electricity bill. Water heaters are second at 12–18%, followed by washers/dryers (5–10%), refrigerators (3–5%), and lighting (5–10%). Space heaters and EV chargers are also significant if used daily.
A kilowatt-hour is the standard unit of electrical energy. It represents 1,000 watts of power used for one hour. For example, a 100W light bulb running for 10 hours uses 1 kWh. Your utility company charges you per kWh consumed.
The US average is about 0.42 kg of CO₂ per kWh (EPA eGRID data). This varies widely — a state using mostly coal might produce 0.9 kg/kWh while one using renewables might produce under 0.1 kg/kWh. Our calculator uses regional averages to estimate your carbon footprint.
Yes — this is called "standby power" or "vampire power." Most electronics draw 1–10 watts even when turned off but still plugged in. Across all devices in a home, this typically adds up to 5–10% of total electricity use, or $100–$200 per year.