Generator Size Calculator: What kVA Generator Do I Need for My Home or Shop?
Free tool · Updated October 3, 2026 · By CouponTalk
Your result
Enter your measurements to see your result.
Quick answer
Add up the running watts of everything that will be on together, then allow for motors: fridges, ACs and water pumps can draw about 3 times their running power for a few seconds when they start. Six LED bulbs, four fans, a TV, a fridge and a 1 HP pump run on about 1.4 kW but need about 3.3 kW at start-up, so a 5 kVA generator (kVA = kW ÷ 0.8, plus headroom).
How to use this calculator
- Enter how many of each appliance must run at the same time.
- Add any other load in watts.
- Use the kVA shown, or the next size up.
Typical appliance power
| Appliance | Running watts | Starting surge |
|---|---|---|
| LED bulb | 10 W | — |
| Ceiling fan | 75 W | — |
| TV | 100 W | — |
| Refrigerator | 200 W | about 3× |
| 1 HP water pump | 750 W | about 3× |
| 1.5 ton AC | 1,500 W | about 3× |
| Washing machine | 500 W | about 2× |
Check appliance labels for exact wattage. Get large installations checked by an electrician.
Frequently asked questions
What is the difference between kW and kVA?
Generators are rated in kVA; usable power in kW is about 0.8 × kVA.
Can a generator run an AC?
Yes, if it covers the AC's starting surge. A 1.5 ton AC typically needs a 5 kVA or larger generator on its own.
Inverter or generator?
For short power cuts and light loads, an inverter is quieter and cheaper to run. Use the inverter battery backup calculator.
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