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Generator kVA Requirement Calculator

Estimate a generator's apparent-power requirement by comparing steady demand with a largest-motor start condition and explicit project reserve.

Inputs

Running and starting loads

Range: 0–1,000,000 kVA

Include loads that remain connected while the selected motor starts.

Range: 0–1,000,000 kVA

Use the motor's running apparent demand from verified design or manufacturer data.

Range: 0–1,000,000 kVA

Use the starting kVA for the selected motor and starter from manufacturer or design data.

Range: 0–500 %

Enter a project-specific reserve; none is assumed by default. This is not an altitude, temperature or duty derating factor.

Result

Governing unreserved scenario (kVA)
130.00
Estimated generator requirement with reserve (kVA)
149.50
Demand during largest motor start (kVA)
130.00
Additional starting step above steady demand (kVA)
40.00
Steady running demand (kVA)
90.00

Formula

Calculation logic

Formula definitions and substituted values.

Before relying on the result

  • Check steady load and motor starting demand
  • Apply an explicit project capacity reserve
  • Estimate a minimum kVA requirement for further verification against the generator manufacturer's transient data.

Related calculators

Estimate a minimum kVA requirement for further verification against the generator manufacturer's transient data.