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Engineering

Transformer Calculator

Use this transformer calculator to calculate calculate transformer secondary voltage, current, and turns ratio.

transformerturns ratiovoltagecurrent

Calculator

Calculate instantly

Calculator Inputs

Choose what you want to calculate, enter realistic values, adjust units where shown, and use the scenario section for repeated-use planning.

Input and Formula Breakdown

This calculator applies the formula Vs/Vp = Ns/Np. Enter each value with the matching unit, and AZCalculate updates the result instantly.

Primary voltage
240 V
Primary turns
1,000
Secondary turns
100
Primary current
2 A
Secondary voltage
24 V
Ideal secondary current
20 A
Turns ratio
10 :1

Scenario and Comparison

Current

24 V

Projected

288

Adjusted

26.4

Visual Comparison

Current result24
Projected usage288
Comparison scenario26.4

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Trust note

Planning estimate

Use this result as a practical estimate. Real-world conditions, local rules, measurement tolerance, and changing inputs can affect the final outcome.

Medium risk contextDifficulty: professionalConfidence estimate: 95/100Reviewed 2026-05-18Reviewed by: Engineering content reviewerCalculator vuces-2.1 / Formula vformula-1.03 sources listed

Formula and Explanation

Vs/Vp = Ns/Np

This calculator applies the formula Vs/Vp = Ns/Np. Enter each value with the matching unit, and AZCalculate updates the result instantly.

Variable descriptions

primaryVoltage(V)
Primary voltage: Primary voltage measured in V, entered as a known value.
primaryTurns
Primary turns: Primary turns, entered as a known value.
secondaryTurns
Secondary turns: Secondary turns, entered as a known value.
primaryCurrent(A)
Primary current: Primary current measured in A, entered as a known value.

Formula Notes

  • Use consistent units for values that are multiplied, divided, or compared.
  • Results may be rounded for readability, while the calculator keeps greater precision internally.
  • Real-world measurements and assumptions can introduce small differences from the calculated estimate.

Common uses

  • Estimate transformer output
  • Compare turns ratios
  • Plan electrical systems

Assumptions

What this calculation assumes

  • Calculations assume compatible engineering units and idealized conditions.
  • Safety factors, tolerances, material variation, and standards should be reviewed separately.
  • Inputs are assumed to describe the same scenario and use compatible units.
  • Results may be rounded for readability.

Avoid mistakes

Quick checks before you rely on the result

  • Ignoring safety factors.
  • Using rated values instead of actual operating conditions.
  • Mixing units, periods, currencies, or measurement systems without converting first.
  • Rounding intermediate values too early.

Step-by-Step Explanation

Follow the reasoning, not only the final number.

  1. 1

    Set up the calculation

    Enter the known values in the calculator fields.

    Starting with clearly defined values and units prevents the most common calculation errors.

  2. 2

    Work through step 2

    Keep the units consistent with the labels shown beside each input.

    This step transforms the known values into the form required by the formula.

  3. 3

    Work through step 3

    Apply the formula: Vs/Vp = Ns/Np.

    This step transforms the known values into the form required by the formula.

  4. 4

    Interpret the result

    Review the primary result and supporting values.

    Compare the result with your real-world goal, such as estimate transformer output.

Worked example

Practical transformer calculator example

Known values

  • Primary voltage: 240 V
  • Primary turns: 1,000
  • Secondary turns: 100
  • Primary current: 2 A

Calculation

  1. 1. Start with the known values shown for this transformer calculator scenario.
  2. 2. Substitute those values into Vs/Vp = Ns/Np.
  3. 3. Evaluate the expression and keep the requested unit and rounding.

Result and meaning

Secondary voltage: 24 V; Ideal secondary current: 20 A; Turns ratio: 10 :1

Calculator guide

About this Transformer Calculator

Calculate transformer secondary voltage, current, and turns ratio.

References

Sources used for this calculator

Found something that does not look right?

We work hard to keep every calculator accurate and useful. If you notice a calculation error, missing option, or unclear explanation, please let us know so we can review and correct it promptly.

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Calculator usage

Usage information loads after the calculator is ready.

FAQ

Transformer Calculator FAQs

How does the transformer calculator work?+

It uses Vs/Vp = Ns/Np and calculates the result from the values you enter.

Can I copy or print the result?+

Yes. AZCalculate calculator pages include copy, share, and print actions.

Should I include a safety factor?+

Yes for real engineering decisions. Use applicable standards and professional review.

Which unit system should I use?+

Use a consistent unit system and convert all inputs before combining them.

How should I use this calculator result?+

Use it as an estimate and compare it with the formula, assumptions, and examples shown on the page.

Why can real-world results differ?+

Real-world inputs can include local rules, changing rates, measurement tolerances, and conditions outside the core formula.

What information do I need for the transformer calculator?+

Enter the known values requested by the calculator. Use the unit selectors where available and make sure the values describe the same scenario.

How accurate is the transformer calculator?+

The calculator follows the formula shown on this page. Accuracy depends on the values, units, assumptions, and rounding used in your scenario.

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