GS / CALCULATOR

Generator sizing calculator

Find a steady state generator rating from load, power factor and target utilization.

Start calculating

Diesel generator model and motor load samples on a capacity planning workbench

GS / INPUTS

Estimate steady-state capacity

Enter load power, load power factor, generator rated power factor and allowed utilization.

Inputs

Power (kW)Load power factor (PF)Generator rated power factorTarget maximum loading (%)

Motor starting check

Largest motor apparent power (kVA, optional)Motor starting current multipleOther apparent load at start (kVA)

Result156.25 kVA

Running apparent load: 125 kVA

Generac sizing guide

Calculation method

Rated kVA ≥ max(load kW / load PF, load kW / rated PF) / allowed load fraction

Interpreting the result

This is a steady-state estimate. Motor starts, load steps, nonlinear loads and environmental derating require separate manufacturer-backed assessment.

The result is an initial estimate based on your inputs. Check equipment nameplates, manufacturer data, installation conditions and project requirements before final selection.

Other tools

kW / kVA calculator Current calculator Fuel consumption calculator Tank runtime calculator ATS sizing calculator