# Transformer Turns Ratio Calculator

Ideal transformer ratio: a = N₁/N₂ = V₁/V₂ = I₂/I₁. Given turns, voltage, or current on either side, compute a and the corresponding voltage/current on the other side; verifies V₁·I₁ = V₂·I₂.

> Canonical page: https://elysiatools.com/en/tools/transformer-turns-ratio

- **Category:** Math & Numbers

- **Keywords:** transformer, turns ratio, voltage ratio, current ratio, ideal transformer, N1/N2, V1/V2, I2/I1, electrical engineering

## Overview

The Transformer Turns Ratio Calculator simplifies electrical engineering tasks by computing the turns ratio, voltages, and currents of an ideal transformer. By utilizing the fundamental relationship where the turns ratio equals the primary-to-secondary voltage ratio and the secondary-to-primary current ratio, this tool quickly solves for missing parameters and verifies power conservation across both windings.

## Inputs

- **Solve From** (select)
- **Primary Turns N₁** (number): Required for Turns mode.
- **Secondary Turns N₂** (number): Required for Turns mode.
- **Primary Voltage V₁ (V)** (number): Required for Voltage mode; optional anchor in other modes.
- **Secondary Voltage V₂ (V)** (number): Required for Voltage mode; optional anchor in other modes.
- **Primary Current I₁ (A)** (number): Required for Current mode; optional anchor in other modes.
- **Secondary Current I₂ (A)** (number): Required for Current mode; optional anchor in other modes.
- **Decimal Places** (number)

## When to use

- When designing winding specifications for step-up or step-down power transformers.
- When calculating secondary voltage output or primary current draw based on known physical turns.
- When validating experimental laboratory measurements against ideal transformer equations.

## How it works

- Select the calculation mode based on your known values: Turns (N1, N2), Voltage (V1, V2), or Current (I1, I2).
- Input the primary and secondary values for your selected mode, along with any optional voltage or current anchors.
- Adjust the decimal places setting to control the precision of the output values.
- Click calculate to generate the turns ratio, compute the corresponding electrical values on the opposite winding, and verify the power balance.

## Use cases

- Determining the required primary and secondary turns for a specific voltage step-down application.
- Calculating the secondary current output when a known load is connected to a transformer with a specified turns ratio.
- Verifying power balance and current scaling in electrical engineering homework or circuit design.

## Frequently asked questions

### What formula does this calculator use?

It uses the ideal transformer formula: a = N1/N2 = V1/V2 = I2/I1, where 'a' is the turns ratio.

### Can I calculate secondary current if I only know the turns and primary current?

Yes. Select the Turns mode, enter N1 and N2, and input your primary current (I1) to calculate the secondary current (I2).

### How is the power conservation check performed?

The calculator multiplies primary voltage by primary current (V1 * I1) and secondary voltage by secondary current (V2 * I2) to verify that input power equals output power.

### Does this calculator account for winding resistance or core losses?

No, this tool calculates parameters for an ideal transformer, assuming zero losses and 100% efficiency.

### What happens if I select Voltage mode?

The calculator determines the turns ratio directly from V1 and V2, and then uses that ratio to scale any provided current values.

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