Generator Size Calculator
Find the generator wattage needed to power your home or job site.
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How It Works
Find the generator wattage needed to power your home or job site. Enter your values and press Calculate for instant results with a full formula breakdown.
Formula
Generator kW = Load x 1.25Quick Reference
Common calculations — results you can verify instantly.
Central AC: 5000W
×1.25 surge
6.25 kVA minimum
Whole home backup
10-20kW typical home
15-25 kVA generator
Small appliances
3000W total
5 kVA generator
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