Cost to Run a 500-watt appliance for 18 hours
Running a 500-watt appliance for 18 hours uses 9 kWh and costs $1.58 at $0.175/kWh. Do that every day and it adds up to $47.25 a month.
Calculate your own cost
- Per hour
- $0.0880.5 kWh
- Per day
- $1.589 kWh
- Per week
- $11.0363 kWh
- Per month (30 days)
- $47.25270 kWh
- Per year
- $574.883,285 kWh
Formula: watts ÷ 1,000 × hours × rate. Edit any box and every number updates instantly.
People also ask
How much does a 500-watt appliance cost per hour?
At $0.175/kWh, it costs $0.088 per hour. The maths: 500 W ÷ 1,000 = 0.5 kWh per hour, × $0.175 = $0.088.
How much does it cost per month?
Used 18 hours a day for 30 days, it costs about $47.25 per month and uses 270 kWh. Change the hours in the calculator above to match how you use it.
How many kWh does it use?
9 kWh per day, 270 kWh per month and 3,285 kWh per year at 18 hours a day. A kWh is one kilowatt (1,000 W) used for one hour. It is the unit on your electricity bill.
How can I lower the cost?
Use it for fewer hours, switch to a lower-wattage model, and check whether your utility offers cheaper off-peak rates. Enter your own rate above to see the effect.
Does my electricity rate change the answer?
Yes, a lot. At 10¢ per kWh the monthly cost is $27.00 and at 30¢ it is $81.00. Find your rate on your bill (total cost ÷ kWh used) and type it into the calculator.
Cost by hours of use
| Used per day | Energy per day | Cost per day | Cost per month | Cost per year |
|---|---|---|---|---|
| 1 hour | 0.5 kWh | $0.088 | $2.63 | $31.94 |
| 2 hours | 1 kWh | $0.175 | $5.25 | $63.88 |
| 3 hours | 1.5 kWh | $0.263 | $7.88 | $95.81 |
| 4 hours | 2 kWh | $0.35 | $10.50 | $127.75 |
| 5 hours | 2.5 kWh | $0.438 | $13.13 | $159.69 |
| 6 hours | 3 kWh | $0.525 | $15.75 | $191.63 |
| 7 hours | 3.5 kWh | $0.613 | $18.38 | $223.56 |
| 8 hours | 4 kWh | $0.70 | $21.00 | $255.50 |
| 9 hours | 4.5 kWh | $0.788 | $23.63 | $287.44 |
| 10 hours | 5 kWh | $0.875 | $26.25 | $319.38 |
| 11 hours | 5.5 kWh | $0.963 | $28.88 | $351.31 |
| 12 hours | 6 kWh | $1.05 | $31.50 | $383.25 |
| 13 hours | 6.5 kWh | $1.14 | $34.13 | $415.19 |
| 14 hours | 7 kWh | $1.23 | $36.75 | $447.13 |
| 15 hours | 7.5 kWh | $1.31 | $39.38 | $479.06 |
| 16 hours | 8 kWh | $1.40 | $42.00 | $511.00 |
| 17 hours | 8.5 kWh | $1.49 | $44.63 | $542.94 |
| 18 hours | 9 kWh | $1.58 | $47.25 | $574.88 |
| 19 hours | 9.5 kWh | $1.66 | $49.88 | $606.81 |
| 20 hours | 10 kWh | $1.75 | $52.50 | $638.75 |
| 21 hours | 10.5 kWh | $1.84 | $55.13 | $670.69 |
| 22 hours | 11 kWh | $1.93 | $57.75 | $702.63 |
| 23 hours | 11.5 kWh | $2.01 | $60.38 | $734.56 |
| 24 hours | 12 kWh | $2.10 | $63.00 | $766.50 |
How we worked it out
- Energy per hour: 500 W ÷ 1,000 = 0.5 kWh
- Cost per hour: 0.5 kWh × $0.175 = $0.088
- Cost per day: × 18 hours = $1.58
- Month and year: × 30 days = $47.25, × 365 days = $574.88
What it costs in different places
Same 500-watt appliance, 18 hours a day. Only the local electricity rate changes.
| Place | Rate per kWh | Cost per month |
|---|---|---|
| United States | $0.175 | $47.25 |
| California | $0.32 | $86.40 |
| Texas | $0.155 | $41.85 |
| New York | $0.25 | $67.50 |
| Florida | $0.155 | $41.85 |
| Illinois | $0.17 | $45.90 |
| Pennsylvania | $0.18 | $48.60 |
| Ohio | $0.17 | $45.90 |
| Washington | $0.115 | $31.05 |
What this estimate assumes
- The appliance draws its full stated wattage the whole time it is on. Real units with a thermostat cycle off and cost less.
- Wattage is the typical label value, not a measured value. Check the label on your own appliance.
- The rate is an approximate residential average. Your bill may include fixed fees, tiers or time-of-use pricing. Edit the rate above.
- A month is 30 days and a year is 365 days.