How Much Electricity Does a Desktop Computer Use?
How much electricity does a desktop computer use? About 270 watts active, tower plus monitor. Enter yours below for the exact cost.
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Desktop computer electricity cost calculator
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How the math works: 120 W × 6 hours ÷ 1,000 = 0.72 kWh a day. × 30 days = 21.6 kWh a month. × $0.165 per kWh (the 2024 U.S. average) = about $3.56 a month.
A basic office-style desktop tower draws roughly 120 watts while active and 30 watts or less asleep, and a separate monitor adds another 150 watts active (30 watts or less asleep) on top of that. A gaming desktop with a dedicated graphics card runs considerably higher.
| Part | Active | Asleep |
|---|---|---|
| Tower | about 120 W | 30 W or less |
| Separate monitor | about 150 W | 30 W or less |
What affects how much electricity a desktop computer uses
- What's inside: a basic office machine with integrated graphics draws far less than a gaming desktop with a dedicated graphics card, which can add several hundred watts under load.
- What you're doing: browsing or word processing barely taxes the processor compared to gaming, video rendering, or running several demanding programs at once.
- What you count: whether the monitor, speakers, and external drives are counted separately or bundled into your desktop figure changes the total.
How to reduce your desktop's electricity use
- Set the computer and monitor to sleep automatically after a short period of inactivity
- Turn the monitor off (or let it sleep) separately when you're only using the tower for a background task
- Use a power strip to fully cut power to peripherals you're not using rather than leaving them on standby
- Consider a laptop instead if your desktop is mainly used for browsing and documents, since it draws a fraction of the power
Typical wattage figure: roughly 120 W while active (30 W or less asleep) for the tower; add roughly 150 W (30 W or less asleep) if a separate monitor is running. Source: DOE-developed appliance energy table, reproduced by Virginia Cooperative Extension (Virginia Tech), publication BSE-301. A gaming desktop with a high-end graphics card draws considerably more than this reference figure, which represents a basic office-style tower. We review this figure periodically and update it if the source changes; last checked September 2026. Cedrick Reese built this desktop computer cost calculator and rechecks the wattage figure against the source above.
Frequently asked questions
How many watts does a desktop computer use?
A basic office-style desktop tower draws roughly 120 watts while active and 30 watts or less while asleep, according to a DOE-developed appliance energy table reproduced by Virginia Cooperative Extension. A separate monitor adds about 150 watts active (30 watts or less asleep). A gaming desktop with a dedicated graphics card runs considerably higher than this office-machine reference figure.
How much does it cost to run a desktop computer?
A 120-watt tower run 6 hours a day at the U.S. average rate of about 16.5 cents/kWh costs roughly $0.12 a day, or about $3.56 a month, not counting the monitor. Use the calculator above with your own system's wattage (tower plus monitor, if you want a combined figure) and rate for an exact number.
Does a gaming desktop use a lot more electricity than a regular one?
Yes, often substantially more, particularly while actively gaming or rendering. A dedicated graphics card alone can draw several hundred watts under load, on top of the processor and other components, so a gaming rig's peak draw can run several times higher than a basic office desktop's.
How can I reduce how much electricity my desktop computer uses?
Set the computer and monitor to sleep automatically after a short idle period, turn the monitor off separately when you only need the tower running, and use a power strip to fully cut power to peripherals you're not actively using.
This page provides estimates based on typical wattage figures for a basic office-style system and the numbers you enter. A gaming desktop with a dedicated graphics card will draw considerably more, particularly under load; actual electricity cost depends on your specific components and usage pattern.