Transformer Voltage and Turns Calculator

Uₚ / Uₛ = Nₚ / Nₛ

Uₚ = (Uₛ * Nₚ) / Nₛ

Uₛ = (Uₚ * Nₛ) / Nₚ

Nₚ = (Uₚ * Nₛ) / Uₛ

Nₛ = (Nₚ * Uₛ) / Uₚ

Uₚ = Primary voltage (V) 

Uₛ = Secondary voltage (V) 

Nₚ = Primary turns 

Nₛ = Secondary turns 

Calculate transformer turns ratio instantly with this professional online tool. Input any three of the following—primary voltage, secondary voltage, primary turns, or secondary turns—and get the missing parameter in real time. Built for electrical engineers and power system designers, it’s fast, accurate, and works on any device—no sign-up required.

Primary Voltage (V_p): AC input voltage applied to the high-voltage winding (in volts).
Secondary Voltage (V_s): AC output voltage from the low-voltage winding (in volts).
Primary Turns (N_p): Number of conductor loops in the primary coil.
Secondary Turns (N_s): Number of conductor loops in the secondary coil.
All calculations assume an ideal transformer model—core losses, leakage flux, and resistance are neglected for theoretical accuracy in design-phase estimation.

The calculator uses the fundamental transformer equation:

V_p/V_s = N_p/N_s

This ratio is critical in power distribution, isolation transformer design, and voltage adaptation for industrial equipment. For example: designing a step-down transformer from 480 V to 120 V with 800 primary turns yields exactly 200 secondary turns—enabling rapid prototyping and specification validation in real-world projects.