Generator Sizing Power Calculator
Enter your total load in kW, power factor, and safety margin to get the required generator size in kVA and kW.
Load Parameters
0%10%20%30%40%50%
Common Power Factors
| Load Type | Typical PF |
|---|---|
| Resistive (heaters, lights) | 1.00 |
| Office equipment / UPS | 0.90 |
| Mixed industrial load | 0.80 |
| Induction motors (loaded) | 0.75 |
| Induction motors (light load) | 0.60 |
Required Generator Size
Minimum kVA
—
apparent power
Minimum kW
—
real power rating
Calculation Breakdown
| Input Load | — |
| Power Factor | — |
| Base kVA (load ÷ PF) | — |
| Safety Margin | — |
| Required kVA | — |
| Required kW (at PF) | — |
Generator Class
—
—
Fill in the load parameters and click Calculate.
Summary
Enter your total load in kW, power factor, and safety margin to get the required generator size in kVA and kW.
How it works
- Enter the total load in kW (real power consumed by your equipment).
- Set the power factor (PF) — typically 0.8 for mixed resistive and inductive loads.
- Choose a safety margin (%) to add headroom above the calculated minimum.
- Click Calculate — the tool divides kW by PF to get required kVA, then applies the safety margin.
- Read the minimum generator kVA and kW ratings to use when selecting a unit.
Use cases
- Size a standby generator for a commercial building or data center.
- Determine the correct generator rating for industrial motor loads.
- Compare generator quotes by knowing the minimum kVA spec you need.
- Verify that an existing generator can handle a newly added load.
- Teach the kVA-vs-kW relationship when commissioning power systems.
Frequently Asked Questions
Last updated: 2026-07-01 ·
Reviewed by Nham Vu