Transformer Calculator

Calculate transformer voltage ratios, turns ratios, output voltage, and approximate primary and secondary current from transformer specifications.

Transformer Information

Primary Voltage (V)

Secondary Voltage (V)

Primary Turns

Secondary Turns

Transformer Power (VA)

0:1Voltage Ratio

0:1Turns Ratio

0 VCalculated Secondary Voltage

0 AApprox. Primary Current

0 AApprox. Secondary Current

How to Use the Transformer Calculator

Enter the primary and secondary voltages to calculate the voltage ratio. You can also enter the number of turns on each winding to calculate the turns ratio.

Transformer Formula

Vₚ ÷ Vₛ = Nₚ ÷ Nₛ

The voltage ratio of an ideal transformer is proportional to its turns ratio. If the primary and secondary turns are known, the calculator can estimate the corresponding secondary voltage.

Current Calculation

When transformer power is entered in volt-amperes (VA), approximate winding current can be calculated using:

Current = VA ÷ Voltage

Actual transformer performance depends on efficiency, load conditions, winding resistance, regulation, and manufacturer specifications. Use this calculator for estimates and verify electrical designs against applicable requirements.