kWh Calculator
Work out kilowatt-hours and dollar cost for any appliance: enter its wattage, how many hours a day you use it, and how many days — the calculator defaults to the latest published US average residential rate (18.83¢/kWh, April 2026 (released June 25, 2026)), or swap in your own rate from your utility bill.
90 kWh ($16.95)
3 kWh/day ($0.56/day) · Est. per year: $206.19
At 18.83¢/kWh — the US residential average was 18.83¢/kWh as of April 2026 (released June 25, 2026) (EIA). Your actual utility rate may differ — check your bill for the exact figure.
Common appliances — kWh/day and monthly cost at 18.83¢/kWh
| Appliance | Watts | kWh/day (3h use) | Est. cost/month |
|---|---|---|---|
| LED light bulb (60W-equivalent) | 15 W | 0.05 | $0.25 |
| Microwave (cooking) | 1,000 W | 3 | $16.95 |
| Toaster (2-slice) | 900 W | 2.7 | $15.25 |
| Refrigerator (average running draw) | 150 W | 0.45 | $2.54 |
| Window AC (8,000 BTU, 120V) | 730 W | 2.19 | $12.37 |
| Central AC (3-ton, 240V) | 3,000 W | 9 | $50.84 |
| Portable space heater | 1,500 W | 4.5 | $25.42 |
| Hair dryer | 1,500 W | 4.5 | $25.42 |
| Vacuum cleaner | 750 W | 2.25 | $12.71 |
| Electric clothes dryer | 3,000 W | 9 | $50.84 |
| Dishwasher | 1,800 W | 5.4 | $30.50 |
| Electric water heater element | 4,500 W | 13.5 | $76.26 |
| 50"–60" LED TV | 120 W | 0.36 | $2.03 |
| Desktop computer | 200 W | 0.6 | $3.39 |
| Ceiling fan | 60 W | 0.18 | $1.02 |
Assumes 3 hours/day of use for comparison — enter the appliance's real wattage and your own hours above for an exact figure.
Default price: EIA Electric Power Monthly, Table 5.6.A (April 2026 (released June 25, 2026)). Appliance wattages: Silicon Valley Power energy chart and cross-checked DOE-style ranges. How we calculate →
How do you calculate kWh from watts?
Energy in kilowatt-hours is kWh = (watts × hours used) ÷ 1,000. A 1000W appliance run for 3 hours a day uses 3 kWh that day; over a 30-day month, that's 90 kWh.
Cost is simply kWh multiplied by your utility's price per kWh: Cost = kWh × price. This calculator defaults to the latest published US average residential rate, but you should replace it with the exact rate on your own electricity bill for an accurate cost.
What's the current average US electricity price?
The US Energy Information Administration (EIA) reported an average 18.83¢ per kWh for residential customers nationwide as of April 2026 (released June 25, 2026) — the most recent month published in the EIA's Electric Power Monthly (Table 5.6.A) at the time this page was last checked.
Rates vary enormously by state — from roughly 12¢/kWh in parts of the Midwest and Mountain West to over 35¢/kWh in Hawaii and California — so the national average is a starting point, not a substitute for your actual utility rate.
How much does it cost to run a space heater?
A typical 1,500W portable space heater run 8 hours a day uses 1,500 × 8 ÷ 1,000 = 12 kWh/day. At the US average rate of 18.83¢/kWh, that's about $2.26/day, or roughly $67.79/month if run daily. Enter your own wattage, hours and local rate above for an exact figure.
Why does 'hours used per day' matter more than nameplate wattage?
Many appliances rarely run continuously at their full nameplate rating — a refrigerator's compressor cycles on and off, and a microwave only draws power while cooking. Estimating kWh from nameplate wattage times 24 hours will overstate real cost for cycling appliances; the appliance table below uses more realistic average running wattages where the difference matters (e.g., a refrigerator's average draw vs. its nameplate rating).
Frequently asked questions
How much does it cost to run a 1,000W appliance for 5 hours a day?
1,000W × 5 hours ÷ 1,000 = 5 kWh/day. At the current US average residential rate of 18.83¢/kWh, that's about $0.94/day, or roughly $28.25 over a 30-day month.
What is the average cost of electricity per kWh in the US?
The EIA's most recent published figure is 18.83¢ per kWh for US residential customers (April 2026 (released June 25, 2026)), from the Electric Power Monthly, Table 5.6.A. This is a national average — check your utility bill for your actual local rate, which can differ by a factor of 3 or more between states.
How much does it cost to run a refrigerator all month?
A refrigerator's average running draw is roughly 150W (not its higher nameplate/startup rating) when averaged over its on/off duty cycle. Running continuously (24h/day) for 30 days, that's 150W × 24 × 30 ÷ 1,000 = 108 kWh — about $20.34/month at the current US average rate.
How do I convert kWh to a dollar cost?
Multiply your kWh usage by your price per kWh (in dollars, not cents — divide the cents figure by 100 first). This calculator does that automatically: enter watts, hours/day and days in the period, and it multiplies the resulting kWh by whatever price you set (defaulting to the latest EIA US average).
Why is my calculated cost different from my actual electric bill?
Your bill includes taxes, fixed customer charges, delivery fees and sometimes tiered or time-of-use rates that a flat cents-per-kWh figure doesn't capture — plus your appliance's real-world wattage may differ from its nameplate rating. Use this calculator for a directional estimate of one appliance's contribution to your bill, and use your utility's exact per-kWh rate (from a recent bill) for the most accurate figure.
Researched & verified by the Calcuris Data & Research Team. How we build and check our tools →