⚡ Free Online Tool
Find the right generator size for your home, jobsite, or outdoor adventure. Select your appliances below and get an instant recommendation.
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⚡ Your Results
How to Use This Calculator
1
Select Appliances
Browse categories or search for appliances. Click to add them to your list.
2
Adjust Quantities
Use the +/− buttons to set how many of each appliance you need to power.
3
View Results
Results update automatically with recommended generator size, charts, and comparison.
Formula Used
Total Running Watts = Sum of (each appliance's running watts × quantity)
Peak Watts = Total Running Watts + Highest Single Surge Difference
Surge Difference = Starting Watts − Running Watts (for the appliance with the largest surge)
Recommended Generator Size = Peak Watts × 1.20 (20% safety margin)
Tips
- Motor-driven appliances (A/C, pumps, compressors) draw 2–3× more watts at startup.
- You don't need to start all appliances simultaneously — stagger large loads.
- At altitudes above 2,000 ft, generators lose ~3% power per 1,000 ft. Size up accordingly.
- Running a generator at 50–75% capacity extends its lifespan.
- Consider fuel type: gas is common but propane/diesel may suit your needs better.
