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Generator Sizing Calculator
Professional kVA generator selection tool. Accounts for motor starting impact, power factor, and future expansion margins.
kVA Sizing
Motor Starting
Standard Ratings
Save & Update
Power Generation
Load & Motor Parameters
Load Parameters
Motor Starting Impact
Calculation Results
Recommended Generator Size
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Standard Rating: —
Total Connected Load
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Base kVA
Motor Starting Impact
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Additional kVA
Safety Margin Applied
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Expansion Factor
Applied Formula
Data Management
Saved Setups (Update / Edit)
Click "Save Setup" to store a configuration. You can click "Update" on a saved setup to load its exact load and motor parameters back into the calculator for quick edits.
No setups saved yet. Calculate a generator size and click "Save Setup".
Engineering Reference
Formulas & Practical Notes
Calculation Steps:
- Convert to kVA: If input is kW, kVA = kW ÷ PF. If kVA, use directly.
- Motor Starting: Additional kVA = Load kVA × (Motor % ÷ 100) × (Starting Factor - 1)
- Margin: Final kVA = (Base kVA + Additional kVA) × (1 + Margin ÷ 100)
- Standard Rating: Rounded up to the nearest standard generator size.
Practical Engineering Notes:
- Generator sizing must carefully consider motor starting inrush current.
- Always keep a margin (typically 20%) for future load expansion.
- Final generator selection should be verified with manufacturer data.
- Consider altitude, temperature, and harmonic loads for precise sizing.
