Free Harmonic Distortion Calculator

Calculate total harmonic distortion (THD) from the fundamental and dominant harmonic component.

V or A
V or A
V or A
V or A

Total Harmonic Distortion

9.05 %

True RMS Value230.94 V or A

Total Harmonic Distortion vs Fundamental Component (V1 or I1)

Total Harmonic Distortion (THD)

THD quantifies how much the waveform deviates from a pure sinusoid.

Formula

THD = sqrt(V3^2 + V5^2 + V7^2 + ...) / V1 x 100%

where V1 is the fundamental component and V3, V5, V7 are harmonic magnitudes. IEEE 519 recommends voltage THD below 5% at the point of common coupling for general systems.

Example Calculation

A 230V supply with 15V 3rd harmonic, 12V 5th, and 8V 7th.

  1. 01RSS harmonics = sqrt(225 + 144 + 64) = sqrt(433) = 20.81
  2. 02THD = 20.81 / 230 x 100 = 9.05%
  3. 03This exceeds the 5% IEEE 519 limit; mitigation is needed.

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