Convert a single-phase kVA rating to kilowatts and see the line current it draws at your supply voltage.
Starting from an apparent-power rating instead? Use the main kVA to kW converter for any power factor.
Every diagram and table on this page updates with the calculator above.
Identical in single and three-phase systems — only the current calculation differs.
The conversion itself carries no phase information at all. What changes between single and three-phase is how much current that apparent power represents, because the three-phase formula includes a √3 factor.
Single-phase current: no √3 anywhere.
| Single phase | Three phase | |
|---|---|---|
| kVA → kW | kVA × PF | kVA × PF |
| Current | kVA × 1,000 ÷ V | kVA × 1,000 ÷ (√3 × V) |
| Typical voltage | 120 / 230 / 240 V | 208 / 400 / 415 / 480 V |
| Practical ceiling | ~20 kVA | Hundreds of kVA |
| Motor starting | Needs a start capacitor | Self-starting |
Above roughly 15–20 kVA the single-phase current becomes awkward: 20 kVA at 230 V is 87 A, which needs heavy cable and a substantial service fuse. Three phase moves the same power at 58% of the current.
On a single-phase supply the reactive component still consumes cable and transformer capacity even though it performs no work. Domestic and light commercial loads are often worse than industrial ones because of lightly loaded motors in fridges, pumps and fans.
A 100 A single-phase service at 230 V is a 23 kVA supply. At 0.85 power factor that is only 19.6 kW of usable load — the difference is a whole electric shower.
Protect the circuit for the current the kVA draws, not the kW. A 10 kVA single-phase supply at 230 V pulls about 43 A regardless of how good the power factor is.
A = kVA × 1,000 ÷ V. Use the actual nominal supply voltage, not a rounded figure.
Grouping, ambient temperature and insulation type all reduce a cable current-carrying capacity.
Choose the next rating above the derated current — 16, 20, 25, 32, 40, 50, 63 A and so on.
Long runs often need a larger cable than the current alone suggests. Most standards limit drop to 3–5%.
Typical single-phase ratings with real power and line current at your selected voltage and power factor.
| kVA | Real power (kW) | Line current (A) |
|---|---|---|
| 1 kVA | 0.85 | 4.3 |
| 2 kVA | 1.7 | 8.7 |
| 3 kVA | 2.55 | 13 |
| 5 kVA | 4.25 | 21.7 |
| 7.5 kVA | 6.38 | 32.6 |
| 10 kVA | 8.5 | 43.5 |
| 15 kVA | 12.75 | 65.2 |
| 20 kVA | 17 | 87 |
| 25 kVA | 21.25 | 108.7 |
| 30 kVA | 25.5 | 130.4 |
| 40 kVA | 34 | 173.9 |
| 50 kVA | 42.5 | 217.4 |
| 75 kVA | 63.75 | 326.1 |
| 100 kVA | 85 | 434.8 |
Because current depends only on kVA and voltage, this grid stays valid whatever the power factor. It is the fastest way to check whether a proposed single-phase supply is realistic.
| kVA | 110 V | 120 V | 220 V | 230 V | 240 V |
|---|---|---|---|---|---|
| 2 kVA | 18.2 | 16.7 | 9.1 | 8.7 | 8.3 |
| 5 kVA | 45.5 | 41.7 | 22.7 | 21.7 | 20.8 |
| 10 kVA | 90.9 | 83.3 | 45.5 | 43.5 | 41.7 |
| 15 kVA | 136.4 | 125 | 68.2 | 65.2 | 62.5 |
| 20 kVA | 181.8 | 166.7 | 90.9 | 87 | 83.3 |
| 30 kVA | 272.7 | 250 | 136.4 | 130.4 | 125 |
| 50 kVA | 454.5 | 416.7 | 227.3 | 217.4 | 208.3 |
About 13.8 kVA at 230 V — older housing stock, tight for electric heating.
About 23 kVA, the common modern domestic supply in much of Europe.
Two 120 V legs giving 240 V; a 200 A panel is roughly 48 kVA.
Before adding an electric vehicle charger, a heat pump or a shower, check the headroom against the service fuse rather than the consumer unit — the fuse is the real limit.
29 calculators built on the same maths as the tool above. Each one has its own inputs, interactive diagrams and worked examples.
Common questions about converting kva to kw (single phase).