What is the formula for Core Loss (Steinmetz)?

The Core Loss (Steinmetz) formula is Pv = K × f^x × B^y, where Pv—Core loss per unit volume (W/m³); K—Steinmetz coefficient (material constant); f—Operating frequency (Hz); B—Peak AC flux density (T); x—Frequency exponent (≈1.1–1.7); y—Flux-density exponent (≈2–3).

What does Pv mean in the Core Loss (Steinmetz) formula?

Pv is Core loss per unit volume (W/m³).

Core Loss (Steinmetz)

Q: How do you calculate Core Loss (Steinmetz)?

Use the formula Pv = K × f^x × B^y. The Steinmetz equation predicts the volumetric core loss of a magnetic material from the switching frequency and the peak AC flux density, using three material constants K, x, and y fitted to the manufacturer’s loss curves. Enter the values you know in the calculator above and it solves for the remaining variable.

Pv = K · f^x · B^y

Calculator

Core Loss Density

Steinmetz K

Frequency

Peak Flux Density

Frequency Exponent

Flux Exponent

Result

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Formula

Pv = K × f^x × B^y

Description

The Steinmetz equation predicts the volumetric core loss of a magnetic material from the switching frequency and the peak AC flux density, using three material constants K, x, and y fitted to the manufacturer’s loss curves. It captures the strong, nonlinear dependence of hysteresis and eddy losses on both frequency and flux swing, and is the basis for choosing core material and operating point in transformers and inductors.

Variables

Pv — Core loss per unit volume (W/m³)
K — Steinmetz coefficient (material constant)
f — Operating frequency (Hz)
B — Peak AC flux density (T)
x — Frequency exponent (≈1.1–1.7)
y — Flux-density exponent (≈2–3)

Practical Notes

K, x, y are valid only over the frequency/flux range they were fitted to; use the improved Generalised Steinmetz (iGSE) for non-sinusoidal waveforms. Multiply Pv by core volume for total core loss.

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