WattCostCalc

How Much Does a 20-watt computer monitor Cost to Run?

A 20-watt computer monitor uses 0.02 kWh per hour and costs $0.004 per hour at $0.175/kWh. Used 8 hours a day, that is $0.028 per day, $0.84 per month and $10.22 per year.

$0.004 per hourat $0.175/kWh

Calculate your own cost

Hours per day:
$0.028per day
Per hour
$0.0040.02 kWh
Per day
$0.0280.16 kWh
Per week
$0.1961.12 kWh
Per month (30 days)
$0.844.8 kWh
Per year
$10.2258.4 kWh

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

People also ask

How much does a 20-watt computer monitor cost per hour?

At $0.175/kWh, it costs $0.004 per hour. The maths: 20 W ÷ 1,000 = 0.02 kWh per hour, × $0.175 = $0.004.

How much does it cost per month?

Used 8 hours a day for 30 days, it costs about $0.84 per month and uses 4.8 kWh. Change the hours in the calculator above to match how you use it.

How many kWh does it use?

0.16 kWh per day, 4.8 kWh per month and 58.4 kWh per year at 8 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?

Lower brightness and set it to sleep after a few minutes. Check your bill for the exact rate and enter it above.

Does my electricity rate change the answer?

Yes, a lot. At 10¢ per kWh the monthly cost is $0.48 and at 30¢ it is $1.44. Find your rate on your bill (total cost ÷ kWh used) and type it into the calculator.

Cost by hours of use

Used per dayEnergy per dayCost per dayCost per monthCost per year
1 hour0.02 kWh$0.004$0.105$1.28
2 hours0.04 kWh$0.007$0.21$2.56
3 hours0.06 kWh$0.011$0.315$3.83
4 hours0.08 kWh$0.014$0.42$5.11
5 hours0.1 kWh$0.018$0.525$6.39
6 hours0.12 kWh$0.021$0.63$7.67
7 hours0.14 kWh$0.025$0.735$8.94
8 hours0.16 kWh$0.028$0.84$10.22
9 hours0.18 kWh$0.032$0.945$11.50
10 hours0.2 kWh$0.035$1.05$12.78
11 hours0.22 kWh$0.039$1.16$14.05
12 hours0.24 kWh$0.042$1.26$15.33
13 hours0.26 kWh$0.046$1.37$16.61
14 hours0.28 kWh$0.049$1.47$17.89
15 hours0.3 kWh$0.053$1.58$19.16
16 hours0.32 kWh$0.056$1.68$20.44
17 hours0.34 kWh$0.06$1.79$21.72
18 hours0.36 kWh$0.063$1.89$23.00
19 hours0.38 kWh$0.067$2.00$24.27
20 hours0.4 kWh$0.07$2.10$25.55
21 hours0.42 kWh$0.074$2.21$26.83
22 hours0.44 kWh$0.077$2.31$28.11
23 hours0.46 kWh$0.081$2.42$29.38
24 hours0.48 kWh$0.084$2.52$30.66

How we worked it out

  1. Energy per hour: 20 W ÷ 1,000 = 0.02 kWh
  2. Cost per hour: 0.02 kWh × $0.175 = $0.004
  3. Cost per day: × 8 hours = $0.028
  4. Month and year: × 30 days = $0.84, × 365 days = $10.22

What it costs in different places

Same 20-watt computer monitor, 8 hours a day. Only the local electricity rate changes.

PlaceRate per kWhCost per month
United States$0.175$0.84
California$0.32$1.54
Texas$0.155$0.744
New York$0.25$1.20
Florida$0.155$0.744
Illinois$0.17$0.816
Pennsylvania$0.18$0.864
Ohio$0.17$0.816
Washington$0.115$0.552

About computer monitor running costs

LED monitors use 20 to 50 W. Larger and higher-refresh-rate screens use more.

Typical sizes: 20 W, 30 W, 50 W, 75 W.

How to spend less: Lower brightness and set it to sleep after a few minutes.

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.

Read the full calculation methodology

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