How to use the transformer calculator
Find secondary voltage and current of an ideal transformer. Enter primary voltage, primary turns, secondary turns, primary current in the fields above; the secondary voltage, secondary current are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- Vp — Primary voltage (V)
- Np — Primary turns
- Ns — Secondary turns
- Ip — Primary current (A)
Worked example
With primary voltage = 230 V, primary turns = 1000, secondary turns = 100, primary current = 1 A, the calculator gives secondary voltage ≈ 23 V; secondary current ≈ 10 A.
Frequently asked questions
What is the formula for the transformer calculation?
Secondary voltage (V) = Vp × Ns / Np. Secondary current (A) = Ip × Np / Ns. Here Vp is primary voltage (V), Np is primary turns, Ns is secondary turns, Ip is primary current (A).
What inputs do I need for the transformer calculator?
You need primary voltage in V, primary turns, secondary turns, primary current in A. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.