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kVA to Amps Calculator

Enter a kVA, kW or amp value, pick the system, and get the other two. Three-phase current is kVA × 1000 ÷ (√3 × line voltage); single-phase current is kVA × 1000 ÷ voltage. kW is kVA × power factor.

Full-load current of common transformer sizes

Rated secondary current, calculated from the nameplate kVA. These are not conductor or breaker sizes.

3-phase kVA208 V480 V600 V
1541.6 A18.0 A14.4 A
3083.3 A36.1 A28.9 A
45124.9 A54.1 A43.3 A
75208.2 A90.2 A72.2 A
112.5312.3 A135.3 A108.3 A
150416.4 A180.4 A144.3 A
225624.5 A270.6 A216.5 A
300832.7 A360.8 A288.7 A
5001,387.9 A601.4 A481.1 A
1-phase kVA120 V240 V
1083.3 A41.7 A
15125.0 A62.5 A
25208.3 A104.2 A
37.5312.5 A156.3 A
50416.7 A208.3 A
75625.0 A312.5 A
100833.3 A416.7 A
1671,391.7 A695.8 A

What this number is, and what it is not

The result is the full-load current a load or transformer draws at its rating. Sizing the conductors, overcurrent protection and service for that load is a separate step: the Canadian Electrical Code (CEC 2024) applies demand factors, continuous-load limits, ambient and bundling corrections and voltage-drop checks, and the utility has its own service requirements. For a permit submission in Alberta that work is done and sealed by an engineer.

Common questions

How do you convert kVA to amps for three phase?

Multiply the kVA by 1000 and divide by 1.732 (the square root of 3) times the line-to-line voltage. A 75 kVA transformer at 208 V gives 75,000 ÷ (1.732 × 208) ≈ 208.2 A.

How do you convert kVA to amps for single phase?

Multiply the kVA by 1000 and divide by the voltage. A 25 kVA single-phase transformer at 240 V is 25,000 ÷ 240 ≈ 104.2 A.

What is the difference between kVA and kW?

kVA is apparent power, the product of voltage and current. kW is the real power that does work, equal to kVA multiplied by the power factor. At a power factor of 0.9, 100 kVA delivers 90 kW.

How many amps is a 600 V, 45 kVA transformer?

On a three-phase 600 V system, 45,000 ÷ (1.732 × 600) ≈ 43.3 A of full-load secondary current.

Can I size a breaker or cable from this result?

No. Breaker and conductor sizes follow the Canadian Electrical Code and depend on the type of load, continuous operation, temperature ratings, installation method and voltage drop. Use this figure as the starting point for that calculation, not the answer.

Related guides

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