Calculate transformer kVA from voltage and current for both single-phase and three-phase systems. Ideal for power distribution, electrical design, industrial equipment, and transformer sizing.
1Φ Utility Pole Feed
A single-phase transformer running on a 2400 V grid with a full-load current rating of 10.42 A delivers exactly 25 kVA of apparent capacity.
3Φ Industrial Supply Plant
An industrial balanced three-phase factory network running at 480 V line-to-line voltage with 120.3 A full-load line current supports a 100 kVA transformer.
Step-down Substation Grid
Checking high-voltage lines running at 13,200 V primary line voltage and 43.74 A line current. Under three-phase operation, this computes to a 1,000 kVA (1 MVA) configuration.
Commercial Panel Load Match
A secondary commercial panel drawing 208 V three-phase voltage with a design limit of 124.9 A primary line current corresponds to a standard 45 kVA rating.
Transformers utilize magnetic flux loops within steel laminations to transfer electrical energy across circuits. Winding loops must be wound uniformly around core limbs to limit leakage inductance and maintain inductive coupling.
Where:
The CalcBoy 1Φ & 3Φ Transformer KVA Calculator evaluates apparent capacity, design limits, and operational rating margins from raw terminal measurements.
Transformer selection and winding calculation require deep engineering precision. Placing incorrect operating voltages or currents across windings can lead to thermal stress, phase unbalanced harmonics, insulation melt, or catastrophic magnetic saturation of steel core laminations. This calculator evaluates alternating current (AC) power configurations using standard industry equations.
By inputting the operating voltage and line current, the tool calculates the corresponding capacity rating for both single-phase and three-phase parameters. It provides immediate results alongside illustrative core topologies to assist with quick engineering checks and on-site distribution reviews.
The factor 1.732 is the square root of 3 (√3). It accounts for line-to-line relationships in balanced three-phase electrical networks where phase waveforms are separated by 120 electrical degrees.
Yes. The mathematical relationship between voltage, current, and kVA is identical for both primary and secondary windings of a transformer.
Transformers are rated in apparent power (kVA) because internal conductor heat dissipation depends on raw current and voltage values, regardless of the load's power factor (PF).
No. This calculator operates under the standard engineering assumption of perfectly balanced line-to-line currents. Unbalanced systems require evaluating individual phases separately.
If negative terminal parameters are provided, the calculator displays the resulting negative power value as-is. This behavior helps engineers inspect phase directional flow offsets during modeling.
Single & Three Phase Transformer kVA Calculator is a free online calculator tool. Use it to get instant, accurate results for your electronics calculations.