Calculation reviewed: 4 October 2026 · Engineering Desk Tools
How to use the kVA to current calculator
Convert apparent power into line current for a single-phase or balanced three-phase supply. Start with measurements or documented values for the equipment and reporting period you actually want to assess. The calculator does not fill in a typical installation for you. Its blank fields help keep a demonstration value from being mistaken for your own operating data.
Choose the required options, enter the values in the labelled units and select Calculate. If a field is rejected, check its range and unit before changing it. The result is accompanied by the equation and assumptions so you can decide whether it answers your engineering question.
Inputs and measurement basis
- Supply. Use three-phase for a balanced three-phase supply and single-phase for a two-wire circuit.
- Apparent power (kVA). Apparent power from the nameplate or supply rating, in kVA.
- Voltage (V). Supply voltage; line-to-line for three-phase. The value must be greater than zero.
Record the measurement source and operating condition. Retain unrounded values for verification.
Method and interpretation
Apparent power differs from active power. A kVA rating describes voltage multiplied by current, while a kW value also includes the effect of power factor. Select the supply arrangement before comparing results. In a balanced three-phase calculation the voltage is measured between phases, so a 400 V entry is not the 230 V phase-to-neutral reading.
I = S × 1000 / (√3 × V) for three-phase; I = S × 1000 / V for single-phase.
Three-phase voltage is line-to-line RMS. This is load current, not a cable size or breaker recommendation. kVA is apparent power; power factor is not needed.
Worked example
This example does not populate the form. Enter your own installation data.
Calculated result: 36.0844 A. Estimated line current
Check the arithmetic independently using the displayed equation. Retain intermediate precision and compare the final value with your equipment documentation.
Quick-reference table
These illustrative rows retain the worked example assumptions except for the varied input. They are not certified ratings or manufacturer data. Use the form for intermediate values.
Common mistakes
Using kW as though it were kVA; entering phase-to-neutral voltage in the three-phase formula; treating calculated operating current as a protective-device rating. Before relying on the output, check the decimal format, unit scale and source of each value. Recheck unusual results against the formula.
Frequently asked questions
Are the example values used automatically?
No. Inputs remain blank when the tool opens or when you clear them. The worked example and table are reading material below the calculator. Enter the actual values you want to check each time, and label saved reports so their context is not lost.
What does the result mean?
The result is the line current the load draws at the entered apparent power and voltage. Use it to compare against the equipment nameplate or a clamp-meter reading, not to select a cable or breaker.
Can I use a zero or a negative value?
The allowed range follows the meaning of each input. A divisor needs a positive value; other fields may allow zero. Check the form labels and error message rather than forcing an invalid value. A rejected input must be corrected before a result can be shown.
Is this a final design or equipment approval?
No. Three-phase voltage is line-to-line RMS. This is load current, not a cable size or breaker recommendation. kVA is apparent power; power factor is not needed. Use the calculation as support for a checked decision, and review equipment documentation and applicable requirements before changing an installation or operating setting.
How can I save or share a calculation?
Calculate first, then use Copy result or Print report. Some maintenance tools also provide a CSV summary. Reports contain your own entered data, so review them before sharing. You can share the public page URL without including plant records or confidential measurements.
How do I report an unexpected result?
Use the Contact page and include the tool URL, input values, units, expected output and the reference you used. Explain the measurement basis. Exclude confidential information.
Related tools and records
Use related calculations with consistent units, periods and equipment scope.
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