Appliance running costs
Cost to run a gaming PC
How much does a 400 W gaming pc cost to run?
A 400 W gaming pc switched on 4 hours per day at 100% duty cycle uses 1.70 kWh of electricity per day. At $0.180/kWh that is $0.31 per day, about $9.31 per average month and $111.76 per year — 621 kWh over the year. Those figures assume a typical wattage and a typical usage pattern; change any input below to match your own appliance and tariff.
Your inputs
Typical example — replace this 400 W default with your appliance’s actual rating for a better estimate.
Adjust to match how hard the appliance actually works — typical range around 100%.
Applies only to the 20 h a day the appliance is switched off, not to the idle part of the duty cycle.
Use the total variable rate from your bill, including delivery charges per kWh.
$9.31
per month (30.44-day average month)
1.70 kWh per day at 400 W
- Per day
- $0.31
- kWh / month
- 52
- kWh / year
- 621
- Per year
- $111.76
Average power across 24 hours
71 W
Daily energy spread evenly over 24 hours. Includes standby draw during switched-off hours when entered.
Cost per running hour
$0.072
While the appliance is actually drawing power.
Effective duty cycle
100%
Share of switched-on time at rated power.
Method
- 400 W = 0.4 kW
- 0.4 kW × 4 h/day = 1.6 kWh/day active
- 5 W standby × 20 h/day off = 0.1 kWh/day standby
- 1.6 + 0.1 = 1.7 kWh/day total
- 1.7 kWh × 0.18 USD/kWh = 0.306 USD/day
- 0.306 × 30.436875 days = 9.314 USD/month
- 1.7 kWh × 365.2425 days = 620.912 kWh/year
- 620.912 kWh × 0.18 USD/kWh = 111.764 USD/year
Monthly figures use a 30.44-day average month, 365.24-day average year.
Assumptions
- Electricity rate of 0.18 USD/kWh (editable).
- Calculations use a year of 365.2425 days and an average month of 365.2425 ÷ 12 = 30.436875 days, so twelve average months equal one year exactly. Displayed values are rounded to 365.24 and 30.44 days, and the rounded figures do not multiply out exactly.
- 5 W standby draw for the 20 hours a day the appliance is switched off. Standby applies only outside the switched-on hours, not to the idle part of the duty cycle, and is included in every kWh and cost figure below.
- Rated power is treated as real power in watts, not volt-amps.
What can change the result?
- Actual load draw versus power supply rating
- Hours gaming versus hours idle or sleeping
- Monitors, which are a separate load
- Frame-rate caps and GPU power limits
$9.31/mo · 52 kWh/mo
How a gaming pc actually draws power
A gaming PC's power supply rating is a ceiling, not a consumption figure — an 850 W PSU in a system that draws 350 W under load still only draws 350 W. Actual draw swings widely: idle on the desktop might be 60–90 W, browsing 100 W, and a demanding game with an uncapped frame rate 400 W or more. Monitors add 20–50 W each and are usually forgotten.
Enter the wattage your system draws while gaming, not the PSU label. The most honest approach is to run the gaming hours and idle hours as two separate calculations and add them. Capping the frame rate is the single most effective way to cut a gaming PC's draw without changing hardware.
Cost at different usage patterns
All rows use 400 W at 100% duty and $0.180/kWh. Only the hours change.
| Hours per day | kWh per day | Per day | Per month | Per year |
|---|---|---|---|---|
| 2 h/day | 0.910 kWh | $0.16 | $4.99 | $59.83 |
| 3 h/day | 1.31 kWh | $0.23 | $7.15 | $85.80 |
| 4 h/day | 1.70 kWh | $0.31 | $9.31 | $111.76 |
| 6 h/day | 2.49 kWh | $0.45 | $13.64 | $163.70 |
Cost across the typical wattage range
Units in this category typically range from 150 W to 900 W. All rows use 4 h/day at 100% duty.
| Power rating | kWh per day | Per day | Per month | Per year |
|---|---|---|---|---|
| 150 W | 0.700 kWh | $0.13 | $3.84 | $46.02 |
| 400 W | 1.70 kWh | $0.31 | $9.31 | $111.76 |
| 900 W | 3.70 kWh | $0.67 | $20.27 | $243.25 |
Worth knowing
Worth knowing
Your next decision
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Your next decision
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Electricity cost tools
- Electricity cost calculatorWatts and hours in, cost per day, month and year out.
- Cost per kWh explainedThree different costs per kWh on one bill, and which one belongs in a calculator.
- Appliance wattage calculatorA configurable appliance list: what this combination draws, and what it costs.
- Watts to run a houseRunning, average and startup watts — separated, not averaged into one range.
Defaults on this page come from the published default registry and the formulas are documented in the methodology.