How much does a desktop computer cost to run?

$5.36 a month

A day of use
$0.18
An hour of running
$0.02
A year
$64.26

120 W, 8 hours a day (tower only, no monitor), at the US average of 18.3¢ per kWh (EIA, June 2026). How we calculate this

Change the watts, hours or rate
I know the appliance's

What it costs at other usage levels

Desktop computer at 120 W and 18.3¢ per kWh
UseA dayA monthA year
1 hour a day$0.02$0.67$8.03
2 hours a day$0.04$1.34$16.07
4 hours a day$0.09$2.68$32.13
8 hours a day typical$0.18$5.36$64.26
24 hours a day$0.53$16.07$192.79
Monthly cost of a desktop computer by usage at the US average rate1 hour a day: $0.67; 2 hours a day: $1.34; 4 hours a day: $2.68; 8 hours a day: $5.36; 24 hours a day: $16.071 hour a day$0.672 hours a day$1.344 hours a day$2.688 hours a day$5.3624 hours a day$16.07

A typical model draws about 120 W (Virginia Cooperative Extension).

A cheaper way to do the same job

Ways to spend less

  • Set it to sleep after 15 minutes idle.
  • Shut it down at night instead of leaving it on.
  • For email and browsing, a laptop does the same job on much less power.

What a desktop computer costs to run in every state

Same usage, each state's latest EIA residential rate, cheapest first
RankStateRateA monthA year
1Nevada13.1¢$3.83$45.94
2Nebraska13.3¢$3.87$46.43
3Utah13.4¢$3.90$46.85
4Louisiana13.5¢$3.94$47.27
5Tennessee14.1¢$4.11$49.30
6Arkansas14.1¢$4.12$49.48
7North Dakota14.1¢$4.12$49.48
8Kentucky14.3¢$4.16$49.97
9Oklahoma14.3¢$4.18$50.21
10Idaho14.4¢$4.20$50.35
11North Carolina14.7¢$4.30$51.65
12Mississippi14.9¢$4.34$52.14
13Washington14.9¢$4.35$52.24
14New Mexico15.1¢$4.40$52.77
15Florida15.1¢$4.41$52.91
16Montana15.1¢$4.42$53.05
17Arizona15.2¢$4.43$53.19
18Wyoming15.2¢$4.45$53.40
19South Dakota15.4¢$4.49$53.82
20West Virginia15.5¢$4.51$54.14
21South Carolina15.6¢$4.54$54.49
22Kansas15.7¢$4.59$55.05
23Iowa15.9¢$4.65$55.82
24Texas15.9¢$4.65$55.85
25Missouri16.2¢$4.74$56.83
26Oregon16.3¢$4.77$57.19
27Georgia16.4¢$4.78$57.33
28Alabama16.4¢$4.79$57.47
29Colorado17.1¢$5.00$60.02
30Virginia17.2¢$5.03$60.34
31Indiana17.5¢$5.11$61.36
32Minnesota17.5¢$5.12$61.39
33Ohio19.2¢$5.60$67.24
34Delaware19.3¢$5.63$67.59
35Wisconsin19.6¢$5.71$68.54
36Illinois19.9¢$5.81$69.69
37Pennsylvania21.7¢$6.35$76.14
38Maryland21.8¢$6.38$76.53
39Michigan23.0¢$6.71$80.56
40Connecticut24.3¢$7.10$85.22
41District of Columbia24.4¢$7.12$85.46
42Vermont24.4¢$7.14$85.64
43New Jersey25.0¢$7.29$87.42
44New Hampshire27.0¢$7.89$94.64
45Alaska28.2¢$8.24$98.85
46Rhode Island29.2¢$8.54$102.42
47New York29.5¢$8.61$103.33
48Maine29.6¢$8.64$103.68
49Massachusetts29.6¢$8.65$103.75
50California34.7¢$10.14$121.73
51Hawaii52.7¢$15.39$184.73

Questions

How much does it cost to run a desktop computer per hour?

About $0.02 an hour. A desktop computer at 120 W uses 0.120 kWh per hour, and at the US average of 18.3¢ per kWh that comes to $0.02.

How much does a desktop computer add to your electric bill?

Used 8 hours a day (tower only, no monitor), about $5.36 a month, or $64.26 a year.

How much does it cost to run a desktop computer 24 hours a day?

Running nonstop, a desktop computer would use 2.88 kWh a day and cost $0.53 a day, or $16.07 over an average month.

How many watts does a desktop computer use?

A typical model draws about 120 W (Virginia Cooperative Extension). Check the label on yours: cost scales directly with watts, so a 20% lower wattage means a 20% lower bill.

Is it cheaper to run a desktop computer or a laptop?

Using a laptop for the same hours instead would cost about $2.23 a month instead of $5.36, saving $3.12.

Which state is cheapest to run a desktop computer in?

Nevada, at 13.1¢ per kWh: $3.83 a month. The most expensive is Hawaii at 52.7¢ per kWh: $15.39 a month. Same appliance, same hours; only the rate differs.

Sources

Usage assumptions (hours a day, season) are ours and listed on the methodology page. Found an error? Tell us.