Choose induced voltage, number of turns, or flux change rate per turn to solve using Faraday’s law magnitudes, with V or mV and Wb/s or mWb/s units.

Uses Faraday’s law magnitudes for fixed coil turns with the same magnetic flux through each turn. Polarity and current direction are not determined.

Related Calculators

Induced Voltage Formula

The calculator uses Faraday’s law in magnitude form for fixed turns experiencing equal magnetic flux. Choose the quantity to solve, then enter the other two values.

E = N × (dPhi / dt)
N = E / (dPhi / dt)
dPhi / dt = E / N
  • E = induced voltage, in volts (V)
  • N = number of coil turns
  • dΦ/dt = magnitude of the rate of change of magnetic flux per turn, in webers per second (Wb/s)

The calculator treats induced voltage as a nonnegative magnitude. In full Faraday’s law, the negative sign shows direction by Lenz’s law. The calculator does not determine polarity or current direction.

Common Units and Conversions

Use consistent units before comparing results. The calculator converts millivolts and milliwebers per second to base units internally.

Quantity Unit Conversion
Voltage mV to V 1 mV = 0.001 V
Voltage V to mV 1 V = 1000 mV
Flux change rate mWb/s to Wb/s 1 mWb/s = 0.001 Wb/s
Flux change rate Wb/s to mWb/s 1 Wb/s = 1000 mWb/s

How Coil Turns Affect Induced Voltage

If This Changes Result Reason
Number of turns doubles Induced voltage doubles E is directly proportional to N
Flux change rate doubles Induced voltage doubles E is directly proportional to dΦ/dt
Flux is constant Induced voltage is 0 No changing flux means no induction

Quick Example

If a coil has 200 turns and the magnetic flux changes at 0.03 Wb/s, the induced voltage is:

E = 200 × 0.03 = 6 V

If you know the voltage and turns instead, divide the voltage by the number of turns to find the required flux change rate.