Generator Sizing Calculator
Find the minimum wattage generator you need. The #1 mistake people make is undersizing — this prevents that.
Add up the running watts of everything you plan to run at once.
Motors (well pumps, AC, refrigerators) need 2–3× their running watts to start. Enter the starting watts of your biggest motor.
Your Results
Minimum Generator Size —
Recommended Size (with headroom) —
Generator Category —
Estimated Fuel/Hour (gas) —
Always size 20–25% above your calculated minimum. Running a generator at 80% load extends its life and efficiency.
📖 Read our generator guides →
— fuel types, quiet options, and solar integration