PSU / PC Power Calculator
Add up the power draw of your CPU, GPU, drives and peripherals to estimate total system wattage and choose a power supply with sensible headroom.
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70% utilization leaves about 30% headroom.
Load at common PSU sizes
Based on 553 W of components at 70% target load, pick a quality unit rated 850 W or higher. Add margin if you plan to overclock or expand.
What is the PSU / PC Power Calculator?
The PSU calculator estimates the total continuous power your PC components draw and recommends a power supply wattage with headroom for transient spikes and future upgrades.
How to use it
- 1Select or enter the wattage for your CPU and GPU.
- 2Add drives, fans, memory and any extra peripherals.
- 3Choose a target utilization (70% leaves about 30% headroom).
- 4Read the estimated load and recommended PSU size.
How it works
Total load is the sum of each component estimate. The recommended PSU size divides the total by the target load percentage so the supply runs in its efficient band rather than at its limit.
Mid-range gaming build
A 125 W CPU plus a 250 W GPU, 3 drives (~15 W), fans and memory total roughly 430 W. At a 70% target load, a 650 W unit is a comfortable choice.
Limitations & notes
- Component figures are typical estimates, not measured values.
- Overclocking, transient GPU spikes and PSU efficiency all affect real draw.
- Always check your GPU vendor’s recommended PSU rating.
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