Generator Sizing Calculator
Estimate running and starting generator requirements from your load rows and explicit simultaneous start scenarios.
A QUICK WALKTHROUGH
How to use this tool
- Enter load rows and scenarios.
- Enter reserve and any referenced derating.
- Calculate and review each scenario and export the report.
Formula and scope
Running totals sum quantity × power and quantity × power / PF. Each scenario replaces the running terms of its starting rows with their starting terms. Adjusted requirement = maximum × reserve / derating. kVA sums are conservative scalar estimates. All loads run except those replaced by starts in each scenario. Every load must occur in a user-specified scenario. Quantities are integers ≥0, PF is (0,1], starting power ≥ running power. Optional derating requires a reference; omitted derating means no correction.
Limitations
Certified generator selection, transients, voltage dip and altitude modelling require manufacturer data and a specific model. This tool does not select a catalogue rating.
GOOD TO KNOW
Common questions
Limitations
Certified generator selection, transients, voltage dip and altitude modelling require manufacturer data and a specific model. This tool does not select a catalogue rating.
How are inputs processed?
Locally in your browser; the report preserves raw inputs and full numeric precision.