Transformer Turns Ratio Calculator
Secondary voltage and current from a transformer's turns ratio.
Enter your values
ⓘ Live results
Results
- Turns ratio
- 10:1
- Secondary voltage
- 24 V
- Secondary current
- 10 A
Quick answer
Vs/Vp = Ns/Np, and Is/Ip = Np/Ns.
Vs = Vp x (Ns/Np)
How to use the Transformer Turns Ratio Calculator
- 1Enter the number of turns on the primary and secondary windings.
- 2Enter the primary voltage and current.
- 3Read the resulting secondary voltage and current (ideal transformer, no losses).
Worked example
Using the values the calculator loads with:
Inputs
- Primary turns1000
- Secondary turns100
- Primary voltage240 V
- Primary current1 A
Results
- Turns ratio10:1
- Secondary voltage24 V
- Secondary current10 A
Frequently asked questions
Step-up or step-down?
If secondary turns exceed primary turns it steps voltage up and current down, and vice versa.
Does power stay the same?
In an ideal transformer, input power equals output power; real transformers lose a small amount to heat.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.