Generator Sizing Calculator

Select your appliances to calculate the right generator size. Covers 400+ devices across 30 categories.

30 Categories 400+ Appliances Instant Results

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Never run generators indoors or in enclosed spaces. Keep at least 20 feet from windows. Carbon monoxide kills.

Generator Sizing Formula

P_running = Σ W_i

Sum of all running watts for all selected appliances running simultaneously.

P_surge = max(S_i − W_i)

Maximum startup surge is the largest difference between starting and running watts across all motors. Only one motor starts at a time.

P_recommended = (P_run + P_surge) × 1.25

Add a 25% safety margin for overload capacity, temperature derating, and unexpected loads.