The short answer
1,500 watts is 12.5 amps on a standard 120 volt U.S. outlet, or 6.25 amps at 240 volts. Running for an hour, it uses 1.5 kWh, which costs about 27 cents at the U.S. average electricity rate of 18.31¢ per kWh (July 2026).
What it costs to run in every state
1,500 watts for 1 hour a day, 30 days a month, at each state's average residential rate (July 2026).
| Alabama | $7.38 | $0.25 | 16.40¢ |
|---|---|---|---|
| Alaska | $12.97 | $0.43 | 28.83¢ |
| Arizona | $6.92 | $0.23 | 15.38¢ |
| Arkansas | $6.45 | $0.21 | 14.33¢ |
| California | $15.12 | $0.50 | 33.61¢ |
| Colorado | $7.65 | $0.26 | 17.00¢ |
| Connecticut | $10.87 | $0.36 | 24.16¢ |
| Delaware | $8.32 | $0.28 | 18.48¢ |
| District of Columbia | $11.34 | $0.38 | 25.21¢ |
| Florida | $6.76 | $0.23 | 15.03¢ |
| Georgia | $7.32 | $0.24 | 16.27¢ |
| Hawaii | $21.60 | $0.72 | 48.00¢ |
| Idaho | $6.18 | $0.21 | 13.73¢ |
| Illinois | $8.65 | $0.29 | 19.22¢ |
| Indiana | $7.53 | $0.25 | 16.73¢ |
| Iowa | $7.20 | $0.24 | 15.99¢ |
| Kansas | $6.87 | $0.23 | 15.27¢ |
| Kentucky | $6.21 | $0.21 | 13.81¢ |
| Louisiana | $5.72 | $0.19 | 12.72¢ |
| Maine | $14.58 | $0.49 | 32.41¢ |
| Maryland | $9.63 | $0.32 | 21.41¢ |
| Massachusetts | $13.72 | $0.46 | 30.49¢ |
| Michigan | $10.37 | $0.35 | 23.05¢ |
| Minnesota | $7.85 | $0.26 | 17.45¢ |
| Mississippi | $6.54 | $0.22 | 14.54¢ |
| Missouri | $7.24 | $0.24 | 16.09¢ |
| Montana | $6.75 | $0.22 | 14.99¢ |
| Nebraska | $6.20 | $0.21 | 13.78¢ |
| Nevada | $5.75 | $0.19 | 12.77¢ |
| New Hampshire | $11.97 | $0.40 | 26.60¢ |
| New Jersey | $11.34 | $0.38 | 25.19¢ |
| New Mexico | $7.24 | $0.24 | 16.09¢ |
| New York | $13.46 | $0.45 | 29.90¢ |
| North Carolina | $6.82 | $0.23 | 15.16¢ |
| North Dakota | $6.03 | $0.20 | 13.41¢ |
| Ohio | $8.75 | $0.29 | 19.45¢ |
| Oklahoma | $6.46 | $0.22 | 14.35¢ |
| Oregon | $7.19 | $0.24 | 15.97¢ |
| Pennsylvania | $9.77 | $0.33 | 21.72¢ |
| Rhode Island | $12.73 | $0.42 | 28.29¢ |
| South Carolina | $6.96 | $0.23 | 15.47¢ |
| South Dakota | $6.92 | $0.23 | 15.37¢ |
| Tennessee | $6.17 | $0.21 | 13.71¢ |
| Texas | $7.15 | $0.24 | 15.88¢ |
| Utah | $5.90 | $0.20 | 13.12¢ |
| Vermont | $10.69 | $0.36 | 23.75¢ |
| Virginia | $7.90 | $0.26 | 17.55¢ |
| Washington | $6.62 | $0.22 | 14.71¢ |
| West Virginia | $7.10 | $0.24 | 15.78¢ |
| Wisconsin | $8.58 | $0.29 | 19.06¢ |
| Wyoming | $6.46 | $0.22 | 14.36¢ |
Common sizes
| Watts | Amps at 120 V | Amps at 240 V |
|---|---|---|
| 100 W | 0.83 A | 0.42 A |
| 500 W | 4.17 A | 2.08 A |
| 1,000 W | 8.33 A | 4.17 A |
| 1,500 W | 12.5 A | 6.25 A |
| 1,800 W | 15 A | 7.5 A |
| 2,400 W | 20 A | 10 A |
| 3,000 W | 25 A | 12.5 A |
| 5,000 W | 41.67 A | 20.83 A |
How it works
The formula
watts = amps × volts
kWh = watts × hours ÷ 1,000
cost = kWh × rate
Assumptions
- Single-phase power with a power factor of 1, which is exact for heaters, kettles, toasters and other resistive loads. Motors draw somewhat more current than watts ÷ volts.
- The breaker size follows the 80% rule for continuous loads (3 hours or more): a 15 A circuit carries 12 A, a 20 A circuit 16 A. Check with an electrician before adding a big load.
- Cost uses the hours a day you enter, 30 days a month.
Worked example: a 1,500 W space heater
1,500 W on a 120 V outlet, 1 hour, at 18.31¢ per kWh
- Amps: 1,500 ÷ 120 = 12.5 A, more than the 12 A a 15 A circuit carries continuously
- Energy: 1,500 × 1 ÷ 1,000 = 1.5 kWh
- Cost: 1.5 × $0.1831 = $0.27 an hour
Ways to cut the cost
- Watts drive the bill, not amps. A 240 V appliance draws half the amps of a 120 V one with the same watts, but costs the same to run.
- Don't stack big loads on one circuit. A heater and a hair dryer on the same 15 A circuit will trip the breaker.
- Check the nameplate. It lists watts or amps; multiply amps by volts if it only shows amps.
- Measure real use. A plug-in usage monitor shows actual watts, which are often lower than the label.
Questions people ask
How many amps is 1,500 watts?
12.5 amps at 120 volts (1,500 ÷ 120), or 6.25 amps at 240 volts. That's more than the 12 amps (80% of 15) a 15 amp circuit should carry for 3 hours or more, so a heater that runs for hours belongs on a 20 amp circuit with nothing else big on it.
How do I convert watts to amps?
Divide the watts by the volts: amps = watts ÷ volts. Most U.S. outlets are 120 volts; dryers, ranges and EV chargers use 240. To go the other way, multiply: watts = amps × volts.
How do I convert watts to kWh?
Multiply the watts by the hours it runs and divide by 1,000. A 1,500 W heater for one hour uses 1,500 × 1 ÷ 1,000 = 1.5 kWh, which costs about 27 cents at the U.S. average rate of 18.31¢ per kWh (EIA, July 2026).
How many watts can a 15 amp circuit handle?
1,800 watts at 120 volts (15 × 120), but only 1,440 watts for loads that run 3 hours or more, under the 80% rule for continuous loads. A 20 amp circuit carries 2,400 watts, or 1,920 continuously.
Why does my appliance draw more amps than watts ÷ volts?
Motors and compressors (fridges, AC, pumps) have a power factor below 1, so they draw more current than their watts suggest, and they draw a burst of current when they start. The formula is exact for heaters, kettles and other resistive loads.