Transformer Sizing Calculator
Calculate transformer capacity and view FLA reference charts
single-phase
kVA
%
kVA
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How to Use This Calculator
1. Select Transformer Type
Choose between single-phase or three-phase transformer based on your electrical system requirements.
2. Enter Load Parameters
Input your load current and voltage. You can select different units (A, mA, kA for current; V, mV, kV for voltage) based on your measurements.
3. Add Spare Capacity (Optional)
Include additional capacity to accommodate future load growth. A typical spare capacity is 20-25% of the minimum required kVA.
4. Review Results
The calculator will display the minimum kVA required and, if applicable, the kVA with spare capacity included.
Formulas Used
Single-phase:
kVA = (Voltage × Current) / 1000
Three-phase:
kVA = (√3 × Voltage × Current) / 1000
With spare capacity:
kVA with spare = Minimum kVA × (1 + Spare% / 100)