Transformer KVA Sizing Calculator
Determine the minimum KVA rating required for a transformer given your load characteristics, supply voltage, and power factor. Results include a recommended standard KVA size with a safety margin.
kW
0–1
V
V
%
Formulas Used
Required KVA:
KVA = kW ÷ Power Factor (PF)
KVA with Safety Margin:
KVAdesign = KVA × (1 + Margin% ÷ 100)
Secondary Full-Load Current:
Single-Phase: I = (KVA × 1000) ÷ Vsecondary
Three-Phase: I = (KVA × 1000) ÷ (√3 × Vsecondary)
Turns Ratio:
a = Vprimary ÷ Vsecondary
Reactive Power:
kVAR = KVA × √(1 − PF²)