kVA to Amps Chart

Translate transformer kVA, UPS kVA, generator kVA, or panel schedule apparent load into line current for common U.S. voltage systems.

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Quick reference table

For transformer and distribution work, kVA-to-amps is a line-current screen that must stay tied to voltage, phase, primary or secondary side, and equipment role. Use the chart to confirm the formula family, then open the transformer calculator when the current will feed a transformer schedule, feeder review, load-bank setup, or equipment submittal.

Transformer kVA to full-load current screen

Transformer kVA to full-load current screen
kVA	120 V 1-phase	240 V 1-phase	208 V 3-phase	480 V 3-phase
3	25.0 A	12.5 A	8.3 A	3.6 A
15	125.0 A	62.5 A	41.6 A	18.0 A
30	250.0 A	125.0 A	83.3 A	36.1 A
45	375.0 A	187.5 A	124.9 A	54.1 A
75	625.0 A	312.5 A	208.2 A	90.2 A
112.5	937.5 A	468.8 A	312.3 A	135.3 A

Where the converted amps usually go next

Where the converted amps usually go next
Work context	Use the amps for	Do not skip
Transformer schedule	Primary or secondary current reference	Nameplate taps and impedance notes
Temporary load bank	Cable set and meter range planning	Cam-lock, lug, and equipment ratings
Panel or switchboard review	Apparent-load comparison	Available fault current and bus rating
Generator or UPS submittal	Output current cross-check	Manufacturer derating and connection details

kVA-to-amps chart to calculator handoff

kVA-to-amps chart to calculator handoff
Search or worksheet need	Use this chart for	Open the calculator when
kVA to amps chart	Screening transformer, UPS, generator, or apparent-load current	Voltage, phase, and equipment role need a traceable calculation
Transformer kVA to amps	Checking common full-load current rows before a schedule review	Primary and secondary sides, taps, or impedance notes must stay attached
Single-phase vs three-phase kVA amps	Confirming which formula and voltage basis apply	Line-to-line voltage, phase, or balanced-load assumptions are not obvious
kVA amps to watts comparison	Keeping apparent current separate from real-power estimates	Power factor or kW must be compared against the apparent-power basis

Formula basis

Single phase: A = kVA x 1000 / V. Three phase: A = kVA x 1000 / (1.732 x VLL).

A is line current in amperes.
kVA is apparent power from the transformer, UPS, generator, or load schedule.
V is circuit voltage for single-phase work.
VLL is line-to-line voltage for balanced three-phase systems.

Worked examples

45 kVA dry-type transformer at 480 V three-phase45 x 1000 / (1.732 x 480) = about 54.1 A on the 480 V side before feeder, protection, and terminal checks.

15 kVA single-phase load at 240 V15 x 1000 / 240 = 62.5 A. Treat that as apparent-load current, not as a finished breaker or conductor selection.

Assumptions. Balanced load and line-to-line voltage assumptions behind this chart.

Three-phase rows assume a balanced load and line-to-line voltage.
The chart converts apparent power only; it does not apply transformer protection rules, demand factors, or conductor ampacity limits.
Equipment nameplates can include voltage taps, temperature limits, enclosure ratings, or derating instructions that change the next decision.

Code and standard notes. Planning limits that should be checked before final equipment selection.

Use the adopted NEC edition, equipment listing, manufacturer instructions, available fault current, terminal temperature ratings, and AHJ requirements before final equipment selection.
For OSHA-covered workplaces, equipment markings, suitability, and installation instructions still need to be followed after a current estimate is calculated.

How to use this chart

1Identify the kVA sourceStart by naming the source of the kVA value: transformer nameplate, UPS output, generator rating, equipment submittal, or load schedule total.

2Match voltage and phase exactlyUse single-phase voltage for single-phase loads and line-to-line voltage for balanced three-phase loads. Do not mix line-to-neutral voltage into a three-phase formula.

3Carry the result into the next reviewAfter the current is calculated, use the calculator output as an input for feeder, lug, protection, metering, and equipment-rating checks.

4Keep nameplate details attachedRecord transformer taps, UPS overload data, generator derating, or manufacturer notes beside the amperes so the number is not separated from the equipment.

Worksheet checklist. Record source basis, review gaps, and assumptions before using the chart result.

Record system voltageWrite the actual project voltage and whether it is single-phase, split-phase, or balanced three-phase before using any table row.
Document equipment roleMark whether the current is being used for transformer scheduling, temporary power, load-bank setup, equipment review, or a design estimate.
Separate current from sizingTreat the calculated amperes as a reference value that must still pass conductor, terminal, overcurrent, enclosure, and manufacturer checks.

Common mistakes to avoid. Review these before turning chart current into an equipment decision.

Using kW as if it were kVA and skipping the power-factor basis behind the equipment rating.
Using line-to-neutral voltage in a balanced three-phase formula that expects line-to-line voltage.
Turning the chart current directly into a breaker size without checking transformer, conductor, terminal, and AHJ requirements.

Frequently asked questions

These answers explain how to use the chart without turning a quick reference into a final design decision.

Is kVA current the same as real power current?

Not always. kVA is apparent power. Real power in kW depends on power factor, so a kVA current screen can be different from a kW-based load estimate.

Can this chart pick a transformer breaker?

No. The chart gives line current only. Protection and conductor decisions also depend on transformer type, voltage, terminals, continuous load, available fault current, and the adopted code path.

Why does 208 V three-phase current look higher than 480 V?

For the same kVA, lower line-to-line voltage requires more line current. That is why the same transformer size produces a much larger current at 208 V than at 480 V.

When should I open the transformer calculator from this chart?

Open the calculator when kVA current must be tied to a specific voltage, phase, primary or secondary side, and equipment role before the next review.