Electricity Cost Calculator
Calculate the electricity cost of any appliance based on wattage and usage.
The Formula
Daily Cost = kWh × Rate ($/kWh)
Monthly Cost = Daily Cost × 30
kWh/day = 1,500 × 8 / 1,000 = 12 kWh
Daily cost = 12 × $0.13 = $1.56
Monthly = $46.80
How to Calculate Electricity Cost
Electricity is billed in kilowatt-hours (kWh). One kilowatt-hour is the energy used by a 1,000-watt appliance running for one full hour. To calculate the cost: convert wattage to kilowatts (divide by 1,000), multiply by hours of use, then multiply by your electricity rate per kWh. A 100-watt light bulb running 8 hours per day at $0.15 per kWh costs: (100 / 1000) x 8 x $0.15 = $0.12 per day, or about $43.80 per year. A clothes dryer at 5,000 watts running 1 hour per day costs (5000 / 1000) x 1 x $0.15 = $0.75 per day, or about $274 per year.
How to Find Your Electricity Rate
Your electricity rate is on your utility bill, typically listed as cents per kWh. The US national average is around $0.13–$0.17 per kWh, but rates vary dramatically by state and season. Hawaii averages over $0.40 per kWh — among the highest in the country. Louisiana and Oklahoma average under $0.10 per kWh. Some utilities charge different rates for different usage tiers — the more you use, the more the marginal kilowatt-hour costs. Check your most recent bill for your actual rate, since that is the number that matters for your household.
The Biggest Electricity Users in Your Home
Heating and cooling (HVAC) typically account for 45–50% of home electricity use, making the thermostat the most powerful energy cost lever you have. Water heating is usually the second largest consumer at 14–18%. Large appliances — dryer, refrigerator, dishwasher — are next. Lighting has become much less significant since the widespread adoption of LED bulbs, which use 75–80% less electricity than incandescent bulbs for the same light output. An EV charger (Level 2) adds roughly 30–60 kWh per charge, which at average rates is $4–$9 per full charge — significantly cheaper than gasoline for equivalent miles.
Frequently Asked Questions
What uses the most electricity in a home?
Heating and cooling (45u201350%), water heating (14u201318%), and major appliances like dryers, refrigerators, and ovens. An electric vehicle charger can also add significantly to your bill.
What is a kWh?
A kilowatt-hour is the energy used by a 1,000-watt appliance running for 1 hour. A typical US household uses about 900 kWh per month.