kVA to Amperes CalculatorFree online other calculator — instant results, no sign-up
Convert apparent power to line current for single- or three-phase AC.
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About the kVA to Amperes Calculator
The kVA to Amperes Calculator converts apparent power in kilovolt-amperes into AC line current using the supply voltage and phase configuration. It supports single-phase supplies and balanced three-phase supplies, applying the appropriate formula for each. With the default settings of 10 kVA, 400 V, and Three-phase, the calculated line current is 14.433757 A.
- Apparent power (kVA)
- The total apparent power supplied to the load, measured in kilovolt-amperes (kVA), defaults to 10.
- Line voltage (V)
- The RMS supply voltage in volts (V), measured line-to-line for three-phase or across the load for single-phase, defaults to 400.
- Phase
- This unitless selection specifies Three-phase or Single-phase operation and defaults to Three-phase.
Formula and method
Three-phase: I = (1000 × S) / (√3 × V). Single-phase: I = (1000 × S) / V. Default example: I = (1000 × 10) / (√3 × 400) = 14.433757 A, rounded to six decimal places.
- IRMS line current in amperes (A).
- STotal apparent power in kilovolt-amperes (kVA), including all three phases for a three-phase load.
- VRMS voltage in volts: line-to-line voltage for three-phase, or voltage across the load for single-phase.
- 1000Conversion factor from kilovolt-amperes to volt-amperes.
- √3The square-root-of-three factor relating total apparent power, line-to-line voltage, and line current in a balanced three-phase system.
Multiply the apparent power in kVA by 1000 to obtain VA. For Three-phase, divide that value by the line-to-line voltage multiplied by √3; for Single-phase, divide by the voltage across the load. Using the default inputs, 10 kVA becomes 10000 VA, and 10000 / (√3 × 400) gives 14.433757 A after rounding.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Apparent power10 kVA
- Line voltage400 V
- PhaseThree-phase
Results
- Result14.433757 A
How to use the kVA to Amperes Calculator
- 1Enter the total apparent power in Apparent power (kVA); leave it at 10 to reproduce the default example.
- 2Enter the RMS supply voltage in Line voltage (V); leave it at 400 for the default example.
- 3Select Three-phase or Single-phase to match the supply; use Three-phase for the default example.
- 4Read the calculated line current in amperes; the default settings produce 14.433757 A.
- 5Confirm that the voltage reference and phase selection match the actual installation before using the result.
Reading your result
The Result row reports RMS line current in amperes (A). For the default balanced three-phase example, 14.433757 A is the current in each line conductor, not a sum of the currents in all three lines. For single-phase operation, the result is the load's line current. Displayed decimal places represent numerical rounding, not guaranteed measurement accuracy.
Limitations
The three-phase calculation assumes a balanced load and uses total three-phase apparent power with line-to-line RMS voltage. It does not determine individual line currents for an unbalanced load, neutral current, starting or inrush current, or harmonic effects. Voltage must be greater than zero, and apparent power should be nonnegative. Power factor is not needed when apparent power is already given in kVA; kW cannot be substituted directly. This result alone is not sufficient to size cables, breakers, or protective devices, which also require applicable electrical-code rules and installation conditions.
Common questions
Should I enter line-to-line or line-to-neutral voltage for Three-phase?+
Enter line-to-line RMS voltage. In the default example, 400 V is the voltage between two line conductors; using line-to-neutral voltage in this formula would give an incorrect line current.
Is the three-phase kVA input per phase or total?+
Enter the total apparent power across all three phases. The default 10 kVA represents the combined load, and the calculator returns 14.433757 A in each line under balanced conditions.
Why does this kVA-to-amperes calculation not ask for power factor?+
Apparent power in kVA already relates directly to RMS voltage and current. Power factor is needed when converting real power in kW to apparent power, but it is not an additional factor in this calculation.
Does the three-phase formula work for both star and delta loads?+
Yes, for balanced loads when you enter total kVA and line-to-line voltage. The output is line current in either case; it is not necessarily the current through an individual winding or delta branch.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.