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PC Power Cost Calculator

Enter watts, hours per day, and your kWh rate to see daily, monthly, and yearly electricity cost for any PC or device.

Device Configuration

W

Not sure? Check PCPartPicker or BuildCores.

%

Effective Power: 400W

Hours

Electricity rate

$/kWh

Type the price per kWh from your bill, with taxes. Not sure? Check GlobalPetrolPrices.

Time of use rates

Add the peak, off-peak, weekend or overnight prices from your plan. Any time they don't cover uses the price above.

Daily Cost
$0.29
1.6 kWh / day
Monthly Cost
$8.76
48.7 kWh / month
Yearly Cost
$105.12
584 kWh / year

How to use this tool

  1. Enter the device wattage and utilization

    Enter the device's maximum or representative load draw in watts, then set utilization to the share of that power it averages while running. For example, 500 W at 80% utilization becomes 400 W effective power. If a wall-socket meter already gives you an average draw, enter that value and set utilization to 100%. Don't use a PSU's rated capacity as the device draw.

  2. Set the hours per day it runs

    Enter how many hours per day the device follows that usage pattern. A gaming PC used 4 hours a day gets 4, while an always-on NAS gets 24. The tool multiplies watts × (utilization ÷ 100) × hours × 365, then divides by 1,000 to get annual kWh.

  3. Enter your electricity rate

    Type the price per kWh from your bill and pick its currency, or start from a dated average for your country or US state. If your plan has peak, off-peak, weekend or overnight prices, add them as time of use rates and set when the device runs. The calculator doesn't model tiered rates, demand charges or fixed daily fees, so use the price you pay for each extra kWh.

  4. Read daily, monthly, and annual cost

    The calculator returns the cost per day, per month, and per year along with total kWh consumed. Use those figures to compare against your utility bill or weigh one device against another before buying or upgrading.

About this tool

The Power Cost Estimator turns wattage into money. Enter a device's maximum or representative load draw, set utilization to estimate its average power while running, add daily runtime and your local electricity rate, and the calculator returns daily, monthly, and annual cost plus total kWh consumption.

If you already measured average draw at the wall, use 100% utilization.

It shows whether leaving a gaming PC on overnight, running a home server 24/7, or upgrading to an OLED TV will be noticeable on your bill.

Use it to size an uninterruptible power supply, decide whether it's cheaper to run a 4090 less often or a 4070 more often, or justify (or veto) a homelab build to your family. Prices work in any currency, and time of use rates let peak, off-peak, weekend and overnight prices apply to the hours the device actually runs.

Formula

Annual cost = watts × (utilization ÷ 100) × hoursPerDay × 365 ÷ 1,000 × rate.

Utilization converts the entered maximum or load wattage into effective average power. The division by 1,000 converts watt-hours to kilowatt-hours, which is how utilities bill you.

A 100 W device at 100% utilization running 24/7 consumes 876 kWh per year and costs about $263 at $0.30/kWh.

When to use it

Use it to compare two GPUs or CPUs with different TDPs over their expected lifespan, size your electricity budget before building a server or mining rig, or decide how aggressively to tune your PC's idle power states.

Pair with the RAM Latency Calculator and Memory & Storage Latency Visualizer to weigh performance against efficiency for a specific workload.

Understanding Idle vs. Load Power

A common mistake when estimating PC running costs is assuming a 1000 W power supply means the computer draws 1000 W constantly.

In reality, a high-end gaming PC might draw 80 W to 120 W while browsing the web or watching video, then ramp up during rendering or demanding games.

Use the utilization slider when one percentage is a fair match for the mix. For more accuracy, calculate active and idle periods as separate scenarios. If you enter a measured blended average, set utilization to 100%.

Popular device profiles

Pre-computed yearly and monthly cost for common devices: gaming PCs, laptops, servers, and consoles.

850 W gaming PC
Current high-end rig running a few hours a day
View details
500 W gaming PC
Mainstream mid-range build
View details
100 W home server
NAS or always-on home lab node
View details

Frequently asked questions

How much does it cost to run a gaming PC 24/7?
At 300 W continuous draw and $0.30/kWh, a gaming PC left on 24/7 costs about $788 per year. If it draws 300 W for 8 hours per day and is off or asleep otherwise, that active use costs roughly $263 per year. Add any idle or standby draw for the other 16 hours separately.
How do I calculate kWh from watts?
Multiply wattage by hours, then divide by 1,000. A 500 W device running for 4 hours uses 500 × 4 ÷ 1,000 = 2 kWh. Multiply by your rate per kWh, such as $0.30/kWh, to get the cost.
What uses more electricity: an RTX 4090 or a typical fridge?
At peak power, the RTX 4090 wins (450 W vs roughly 100-150 W compressor draw). Annual consumption is the opposite: a fridge runs 24/7 at an average of 40-60 W, roughly 350-526 kWh a year. That's more than many gaming PCs use when run only a few hours daily.
Does a 1000 W PSU use 1000 W all the time?
No. A PSU is rated for its maximum output capacity, but actual draw depends on what the components need. A system with a 1000 W PSU at idle might pull 80 W from the wall, jumping to 400-600 W under gaming load.
How much does an always-on TV or server cost per year?
At 100 W continuous draw and $0.30/kWh, a device running 24/7 costs $263/year. A home NAS at 50 W costs $131/year, and a 65-inch OLED TV watched 4 hours/day at 150 W costs about $66/year.
Why is my electricity bill higher than the estimator predicts?
The estimator treats the wattage input as a maximum or representative load and multiplies it by utilization to estimate average draw while the device runs. If you enter an average measured with a wall-socket meter, set utilization to 100% so it isn't reduced twice. Add idle and standby periods as separate scenarios when they fall outside the hours entered.
How do time of use rates change what a PC costs to run?
Time of use plans charge more for each kWh at peak times, often weekday evenings, and less overnight or on weekends. So the same PC can cost a lot more when it mostly runs at peak times. Add each period's price and hours in the calculator, set when the PC runs, and the breakdown shows what each period costs over a year.
Where do the average electricity rates come from?
US state averages come from the U.S. Energy Information Administration, European countries from Eurostat, and Great Britain from Ofgem's price cap. Each one shows the period it covers and the date it was checked. An average can be far from your own plan, so use the rate on your bill when you have it.
How can I reduce my PC's power consumption?
Undervolt your CPU and GPU, use sleep states, and cap your frame rate. Undervolting lowers voltage, often with little performance loss. Sleep states let the PC draw minimal power when it's inactive. A frame rate cap at your monitor's refresh rate stops the GPU from rendering frames you can't see.
What is a TDP and is it the same as power draw?
Not exactly. TDP (Thermal Design Power) is the amount of heat the cooling system needs to dissipate, not the exact electrical wattage drawn from the wall. The two numbers are closely related (a 250 W TDP CPU will draw roughly 250 W under full load), but modern CPUs can often boost slightly above their rated TDP.

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