Generator Sizing Calculator
Watts needed to power what you care about.
Pick what you want to power
Generator size needed
0 W
peak (start) capacity
Running watts
0 W
Largest surge
+0 W
Sum running watts of everything you want to power, then add the largest single surge (motors and compressors briefly need 2 to 4× their running watt). A 7,500W generator handles most household essentials. Whole-house generators are sized to the service panel - typically 10,000 to 22,000W.
About
Pick the appliances you want to keep running. The tool sums running watts and adds the largest single startup surge to size a generator.
How to use
- Tick the appliances you need.
- Add custom items.
FAQ
Why does the surge only count once?+
Motors and compressors briefly need 2 to 4× their running watts to start. The generator only needs to handle one surge at a time. Stagger which appliances you turn on after a power cut.