Bode Plot Generator

Automatically Draw Gain & Phase Diagrams from Transfer Functions

Simply enter the transfer function coefficients to automatically draw Bode plots (gain and phase diagrams). Gain margin, phase margin, and cutoff frequency are calculated automatically. A free online tool ideal for control engineering study and design.

T = 1.00
ζ = 0.50
ωn = 10.0
Kp = 1.0
Ki = 1.0
Kd = 0.1
Comma-separated. e.g. 1, 2 means s + 2
Comma-separated. e.g. 1, 2, 1 means s² + 2s + 1
Transfer Function G(s)
G(s) = 1s² + 2s + 1
Gain Margin (GM)
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Phase Margin (PM)
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Gain Crossover Frequency
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Cutoff Frequency (-3dB)
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How to Read a Bode Plot

A Bode plot consists of two graphs stacked vertically. The upper graph is the gain plot (magnitude response), and the lower graph is the phase plot (phase response). The horizontal axis uses a logarithmic frequency scale (rad/s), allowing you to view system characteristics across a wide frequency range at once.

Stability Assessment

If both the gain margin and phase margin are positive, the closed-loop system is stable. Generally, a gain margin of at least 6 dB and a phase margin of 30 to 60 degrees are recommended.

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