Generator Size Calculator — KVA Load & Surge
Calculate the right generator size for your home or office. Enter appliances to get total load, surge power, and recommended KVA.
Add Appliances
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2–3× running for motors; same as running for resistive loads Quick add:
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Recommended KVA
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Total Running Watts
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Total Surge Watts
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Min. Generator kW
Generator Size Guide
| Generator Size | Real Power (kW) | Suitable For |
|---|---|---|
| 1.5 KVA | 1.2 kW | Lights, fans, phone charging only |
| 2.5 KVA | 2 kW | Small flat, fridge + lights + TV |
| 5 KVA | 4 kW | 2-bed flat, no AC |
| 7.5 KVA | 6 kW | 3-bed house, 1 AC unit |
| 10 KVA | 8 kW | Large home, 2–3 AC units |
| 20 KVA | 16 kW | Small office or shop |
Frequently Asked Questions
How do I choose the right generator size?
Add up the wattage of all appliances you want to power simultaneously. Add a 25% safety buffer. Also check surge/startup wattage for motors (AC, fridge, pumps) — they need 2–3× running watts at startup.
What is the difference between KVA and KW for generators?
KW (kilowatt) is real power. KVA (kilovolt-ampere) is apparent power. KW = KVA × power factor. For home appliances, power factor ≈ 0.8. So a 5 KVA generator delivers about 4 KW of real power.
What size generator do I need for a 3-bedroom house in Nigeria?
A typical 3-bedroom Nigerian home needs 4–6 KVA for essential loads (lights, fans, fridge, TV, water pump) or 7.5–10 KVA if including one air conditioner.
Why do motors need extra startup (surge) power?
Electric motors draw 2–7× their running wattage for the first few seconds to overcome inertia. Air conditioners, fridges, and water pumps all have high startup surges. Your generator must handle this peak without tripping.
What are the most common generator sizes in Nigeria?
1 KVA (small office/room), 2.5 KVA (basic home), 5 KVA (mid-size home), 7.5 KVA (3-bed with AC), 10 KVA (large home), 20–100 KVA (industrial/commercial).