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Generator Wattage Calculator

Size a generator from running and starting watts.

Calculated Output

Generator size needed (W) 5,200

Size (kW) 5.2

Formula: size = running watts + largest starting surge

Step-by-Step Breakdown

1. Values used:

2. Total running watts = 3,000 W

3. Largest starting surge = 2,200 W

5. Generator size needed = Total running watts + Largest starting surge = 3,000 + 2,200 = 5,200W

6. Size = 5.2kW

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The math behind it

Add the total running watts to the single largest starting surge (motors briefly draw extra).

3,000 running + 2,200 surge → 5,200 W.

Why only one surge?

Appliances rarely start at the exact same instant, so add only the biggest surge.