Engineering CalculationDG Set Size Calculator - Diesel Generator kVA for your Load
Size a diesel generator from the connected load, running load and the largest motor start, and get a recommended DG set kVA.
Open the calculator →Formula
kVA = kW / power factor (DG sets are rated at 0.8 PF)
Check the largest motor starting kVA and step load against the DG's transient capability
Worked example
160 kW running load at 0.8 power factor
Running kVA = 160 / 0.8 = 200 kVA; keeping running load near 80 % of rating gives 250 kVA → choose the next standard DG size
Where engineers use it
- Backup power for factories, hospitals and buildings
- Fire pump and emergency load DG
- Checking an existing DG for added load
How to use
- Click Open the calculator. It runs free in your browser, on desktop or phone.
- Enter your values. Units and typical ranges are shown next to each input.
- Read the result and the step-by-step working, then print or add it to your Project BOQ.
Questions
Why does motor starting matter?
A direct-on-line start draws several times the running current, which can make the voltage dip and stall a small DG. The tool checks this.