kVA to Amps Calculator
Convert apparent power and voltage to current, or reverse amps to kVA, with explicit single-phase and balanced three-phase voltage bases.
How to Use
- Choose the direction - use kVA to amps when apparent power is known, or switch to amps to kVA for the reverse conversion.
- Choose the exact voltage basis - single-phase uses V × I. Balanced three-phase line-to-line uses √3 × VLL × I. Balanced Wye line-to-neutral uses 3 × VLN × I.
- Do not mix VLL and VLN - 480 V line-to-line and 277 V line-to-neutral describe the same common Wye system but belong in different formulas. Select the basis that matches the voltage you enter.
- Do not enter power factor - kVA is already apparent power. PF is needed only when starting from real power in kW, not when kVA itself is known.
A 25 kVA load at 480 V balanced three-phase line-to-line is about 30.07 A. The same 25 kVA on a 480Y/277 V system can also be calculated from 277 V line-to-neutral using the 3 × VLN relationship and gives the same current apart from rounding. The calculator also reverses amps and voltage back to kVA.
Pick the Voltage Basis Before Converting
kVA Is Apparent Power, Not Real Power
Kilovolt-amperes measure apparent power. Once kVA is known, converting it to current needs voltage and phase but not power factor. Power factor enters only when the starting value is real power in kW.
Starting from kW is a different job. Real power equals apparent power multiplied by power factor, so kW must first be converted to kVA when PF is below 1.
The reverse mode uses exactly the same relationships in the other direction. It is useful when line current and voltage are known and you want the corresponding apparent-power load.
Converted current is not automatically a breaker rating. If the next question is a general overcurrent-device planning check, use the Breaker Size Calculator and still verify any equipment-specific rules.
Three-Phase Line-to-Line vs Line-to-Neutral
For a balanced three-phase system using line-to-line voltage, S = √3 × VLL × I. For a balanced Wye system using line-to-neutral voltage, S = 3 × VLN × I.
Those are not two competing formulas. In a balanced Wye system, VLL = √3 × VLN, so they describe the same total apparent power. The important part is selecting the formula that matches the voltage value in front of you.
Example: 480Y/277 V describes approximately 480 V line-to-line and 277 V line-to-neutral. Enter 480 V with the line-to-line option or 277 V with the line-to-neutral option. Do not enter 277 V while leaving the calculator on line-to-line.
Common Three-Phase kVA-to-Amps Chart
| kVA | 208 V L-L | 240 V L-L | 480 V L-L | 600 V L-L |
|---|---|---|---|---|
| 15 | 41.64 A | 36.08 A | 18.04 A | 14.43 A |
| 25 | 69.39 A | 60.14 A | 30.07 A | 24.06 A |
| 45 | 124.90 A | 108.25 A | 54.13 A | 43.30 A |
| 75 | 208.18 A | 180.42 A | 90.21 A | 72.17 A |
| 100 | 277.57 A | 240.56 A | 120.28 A | 96.23 A |
| 112.5 | 312.27 A | 270.63 A | 135.32 A | 108.25 A |
| 150 | 416.36 A | 360.84 A | 180.42 A | 144.34 A |
| 225 | 624.54 A | 541.27 A | 270.63 A | 216.51 A |
Balanced three-phase line current from I = kVA × 1000 ÷ (√3 × VLL). Rounded to two decimals.
Balanced Wye Voltage Pairs
| System notation | Line-to-line voltage | Line-to-neutral voltage | Use in this calculator |
|---|---|---|---|
| 208Y/120 V | 208 V | 120 V | 208 V with 3-phase L-L, or 120 V with 3-phase L-N |
| 480Y/277 V | 480 V | 277 V | 480 V with 3-phase L-L, or 277 V with 3-phase L-N |
| 600Y/347 V | 600 V | 347 V | 600 V with 3-phase L-L, or 347 V with 3-phase L-N |
Nominal system labels are shown for orientation. Use the voltage that matches the selected basis and the actual system data.
Common Single-Phase kVA-to-Amps Chart
| kVA | 120 V | 240 V |
|---|---|---|
| 5 | 41.67 A | 20.83 A |
| 10 | 83.33 A | 41.67 A |
| 15 | 125.00 A | 62.50 A |
| 25 | 208.33 A | 104.17 A |
| 50 | 416.67 A | 208.33 A |
Single-phase current from I = kVA × 1000 ÷ V.
kVA and Current Formulas
Let S be apparent power, V voltage, and I line current:
3-phase L-L, kVA to amps = I = kVA × 1000 ÷ (√3 × VLL)
3-phase L-N, kVA to amps = I = kVA × 1000 ÷ (3 × VLN)
Single-phase, amps to kVA = kVA = V × I ÷ 1000
3-phase L-L, amps to kVA = kVA = √3 × VLL × I ÷ 1000
3-phase L-N, amps to kVA = kVA = 3 × VLN × I ÷ 1000
The three-phase line-to-line mode assumes a balanced system. The line-to-neutral mode specifically assumes a balanced Wye system.
Authoritative Technical Sources
- Eaton publishes direct formulas for current when kVA is known, including I = kVA × 1000 ÷ V for single-phase and I = kVA × 1000 ÷ (√3 × V) for three-phase systems.Eaton - Power Distribution Systems Reference Data
- Siemens publishes the same single-phase and three-phase line-current relationships together with full-load-current tables across common transformer voltages.Siemens - Series H Transformers, Appendix A
Next Steps
After converting kVA and current, use the result in the next calculation you actually need:
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