WattCostCalc

Cost to Run a 400-watt appliance for 10 hours in Illinois

Running a 400-watt appliance for 10 hours uses 4 kWh and costs $0.68 at $0.17/kWh in Illinois. Do that every day and it adds up to $20.40 a month.

$0.68 for 10 hoursat $0.17/kWh

Calculate your own cost

Hours per day:
$0.68per day
Per hour
$0.0680.4 kWh
Per day
$0.684 kWh
Per week
$4.7628 kWh
Per month (30 days)
$20.40120 kWh
Per year
$248.201,460 kWh

Formula: watts ÷ 1,000 × hours × rate. Edit any box and every number updates instantly.

People also ask

How much does a 400-watt appliance cost per hour?

At $0.17/kWh, it costs $0.068 per hour. The maths: 400 W ÷ 1,000 = 0.4 kWh per hour, × $0.17 = $0.068.

How much does it cost per month?

Used 10 hours a day for 30 days, it costs about $20.40 per month and uses 120 kWh. Change the hours in the calculator above to match how you use it.

How many kWh does it use?

4 kWh per day, 120 kWh per month and 1,460 kWh per year at 10 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 $12.00 and at 30¢ it is $36.00. Find your rate on your bill (total cost ÷ kWh used) and type it into the calculator.

Cost by hours of use in Illinois

Used per dayEnergy per dayCost per dayCost per monthCost per year
1 hour0.4 kWh$0.068$2.04$24.82
2 hours0.8 kWh$0.136$4.08$49.64
3 hours1.2 kWh$0.204$6.12$74.46
4 hours1.6 kWh$0.272$8.16$99.28
5 hours2 kWh$0.34$10.20$124.10
6 hours2.4 kWh$0.408$12.24$148.92
7 hours2.8 kWh$0.476$14.28$173.74
8 hours3.2 kWh$0.544$16.32$198.56
9 hours3.6 kWh$0.612$18.36$223.38
10 hours4 kWh$0.68$20.40$248.20
11 hours4.4 kWh$0.748$22.44$273.02
12 hours4.8 kWh$0.816$24.48$297.84
13 hours5.2 kWh$0.884$26.52$322.66
14 hours5.6 kWh$0.952$28.56$347.48
15 hours6 kWh$1.02$30.60$372.30
16 hours6.4 kWh$1.09$32.64$397.12
17 hours6.8 kWh$1.16$34.68$421.94
18 hours7.2 kWh$1.22$36.72$446.76
19 hours7.6 kWh$1.29$38.76$471.58
20 hours8 kWh$1.36$40.80$496.40
21 hours8.4 kWh$1.43$42.84$521.22
22 hours8.8 kWh$1.50$44.88$546.04
23 hours9.2 kWh$1.56$46.92$570.86
24 hours9.6 kWh$1.63$48.96$595.68

How we worked it out

  1. Energy per hour: 400 W ÷ 1,000 = 0.4 kWh
  2. Cost per hour: 0.4 kWh × $0.17 = $0.068
  3. Cost per day: × 10 hours = $0.68
  4. Month and year: × 30 days = $20.40, × 365 days = $248.20

Illinois electricity prices

Illinois pays about $0.17 per kWh, which is 3% lower than the US average of $0.175. The same appliance would cost $21.00 a month at the national average.

What it costs in different places

Same 400-watt appliance, 10 hours a day. Only the local electricity rate changes.

PlaceRate per kWhCost per month
United States$0.175$21.00
California$0.32$38.40
Texas$0.155$18.60
New York$0.25$30.00
Florida$0.155$18.60
Illinois$0.17$20.40
Pennsylvania$0.18$21.60
Ohio$0.17$20.40
Washington$0.115$13.80

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 in Illinois. 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.

Read the full calculation methodology

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