How many kVA do you need?
Pick what you will run and add quantities. The result is a first estimate that our technician reviews with you before confirming.
Add your loads to see the result.
Method: total running load + twice the largest motor’s rating to cover starting current, divided by a 0.8 power factor, then 20% headroom, rounded up to the nearest standard size. Equipment ratings shown are typical values; use your nameplates for accuracy.
How many kVA do I need? The method in four steps
- Add the kW of everything that will run at the same time.
- Add twice the largest motor (AC, pump, compressor) to cover starting current.
- Divide by a 0.8 power factor to get kVA.
- Add 20% headroom, then choose the nearest standard size.
Start from a ready example
Common sizing questions
How many kVA do I need?
Add the kW of everything running together, add twice the largest motor to cover starting current, divide by 0.8, then add 20% headroom. The calculator above does this automatically.
What is the difference between kVA and kW?
kVA is the apparent power a generator is rated in and kW is the real power. kW ≈ kVA × 0.8, so a 100 kVA unit gives about 80 kW.
What size does a camp need?
About 15 kVA for a small camp with one AC, 30 kVA for a family camp with three AC units and a kitchen, and 60 kVA for a commercial camp with six AC units.
Why does the generator trip when the AC starts?
Because an AC draws around three times its rating at start-up. If starting current was not allowed for, the generator is too small.
Is the calculator accurate?
It gives a good first estimate using typical equipment ratings. For accuracy use your nameplates; our technician reviews the result with you before the order is confirmed.