How do I make a Bode plot?

Describe your system type (low-pass, high-pass, band-pass, etc.), give the corner or cutoff frequency, and say whether you want the magnitude plot, phase plot, or both. Figviz draws the curves, labels the axes, and marks the corner frequency. You can refine the prompt to adjust the frequency range or add annotations.

Is the Bode plot generator free?

Yes. You can generate Bode plots using the free credits every account starts with. Buying any pay-as-you-go credit pack removes the watermark and unlocks higher resolutions. Credits never expire.

What is the corner frequency on a Bode plot?

The corner frequency (also called the cutoff frequency or break frequency) is the frequency at which a filter begins to roll off. On the magnitude plot it marks the transition between the passband and the stopband, and at that exact frequency the actual response is 3 dB below the flat asymptote for a first-order system.

What is the difference between a magnitude plot and a phase plot?

The magnitude plot shows the gain of the system in decibels (dB) at each frequency, revealing how much the system amplifies or attenuates signals. The phase plot shows the phase shift in degrees at each frequency, revealing the time delay the system introduces. A full Bode plot includes both, stacked on a shared log-frequency x-axis.

Can I use it for an engineering or physics class?

Yes. Download a high-resolution PNG (up to 4K) for lab reports, slides, and worksheets. Figviz is useful for visualizing filter behavior and understanding frequency response concepts. Always verify the curves match your calculated values before submitting for assessment, and diagrams from a paid account can be used in your own teaching materials.

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Bode Plot Generator Bode Plots

Describe a filter or control system and get a clean, labeled Bode plot in seconds, with the magnitude curve in dB, the phase curve in degrees, the corner frequency marked, and the log-frequency axis scaled correctly. Low-pass, high-pass, band-pass, and more.

✓Magnitude and phase plots✓Corner frequency labeled✓Log-frequency x-axis✓Slide and print readyLast updated: 2026-06-21

Bode Plot Examples

Browse Bode plots made with Figviz, or generate your own above

Low-Pass Filter Bode Plot

A first-order low-pass filter Bode plot with the -20 dB/decade rolloff and -90 degree phase shift labeled.

low-passmagnitudephase

High-Pass Filter Bode Plot

A first-order high-pass filter Bode plot with the +20 dB/decade rise and +90 degree phase shift labeled.

high-passmagnitudephase

Band-Pass Filter Bode Plot

A band-pass filter Bode plot with both cutoff frequencies and the center frequency marked.

band-passmagnitudecutoff

Bode Plot with Corner Frequency Marked

A Bode plot highlighting the corner frequency and showing both the actual curve and the asymptotic Bode approximation.

corner frequencyasymptoteannotation

Magnitude Plot in dB vs Log Frequency

A standalone magnitude Bode plot in dB vs log frequency with labeled slope and gain values.

magnitudedBlog frequency

Phase Plot in Degrees vs Log Frequency

A standalone phase Bode plot showing the phase shift in degrees vs log frequency with key angles annotated.

phasedegreeslog frequency

Prompt templates you can copy

Start with one of these examples, then adapt the subject, labels, data, or layout for your own use.

Low-Pass Filter Bode Plot

A first-order low-pass filter Bode plot with the -20 dB/decade rolloff and -90 degree phase shift labeled.

Create a labeled Bode plot for a first-order low-pass RC filter with a corner frequency of 1 kHz. Show the magnitude plot in dB and phase in degrees vs log frequency from 10 Hz to 100 kHz. Mark the corner frequency and label the -20 dB/decade slope. Classic engineering style, grid lines. White background.

High-Pass Filter Bode Plot

A first-order high-pass filter Bode plot with the +20 dB/decade rise and +90 degree phase shift labeled.

Create a labeled Bode plot for a first-order high-pass filter with a corner frequency of 500 Hz. Show magnitude in dB and phase in degrees vs log frequency from 10 Hz to 50 kHz. Mark the corner frequency and label the +20 dB/decade slope. Classic black-on-white style with grid. White background.

Band-Pass Filter Bode Plot

A band-pass filter Bode plot with both cutoff frequencies and the center frequency marked.

Create a labeled Bode plot for a second-order band-pass filter with a center frequency of 2 kHz and a bandwidth of 400 Hz. Show the magnitude in dB vs log frequency. Mark the lower cutoff, upper cutoff, and center frequency. Classic engineering style with grid. White background.

Bode Plot with Corner Frequency Marked

A Bode plot highlighting the corner frequency and showing both the actual curve and the asymptotic Bode approximation.

Create a labeled Bode plot for a first-order system showing both the exact magnitude curve and the asymptotic straight-line Bode approximation. Mark the corner frequency at 1 kHz with a dotted vertical line and annotate the 3 dB error at that point. Log-frequency x-axis, magnitude in dB y-axis. White background.

What is a Bode plot generator?

A Bode plot generator is a tool that produces frequency response plots for filters, amplifiers, and control systems. A Bode plot consists of two graphs plotted on a shared log-frequency x-axis: the magnitude plot (gain in decibels) and the phase plot (phase shift in degrees). With Figviz you describe the system in plain language and get a clean, labeled diagram in seconds, without setting up simulation software or drawing the curves by hand.

How to make a Bode plot

Identify your system type (for example, first-order low-pass, second-order band-pass).

State the corner or cutoff frequency (for example, 1 kHz or 1000 rad/s).

Specify whether you want the magnitude plot, the phase plot, or both on the same axes.

Choose a style and aspect ratio, then generate.

Check the labeled corner frequency, slopes, and asymptotes, and refine the prompt if needed.

Magnitude vs phase plots

The magnitude plot shows how much a system amplifies or attenuates a signal at each frequency, measured in decibels (dB). A first-order low-pass filter rolls off at -20 dB per decade above the corner frequency; a second-order filter rolls off at -40 dB per decade. The phase plot shows the phase shift the system introduces at each frequency, measured in degrees. A first-order low-pass filter introduces up to -90 degrees of phase lag; a second-order filter introduces up to -180 degrees. Together the two plots fully describe the steady-state frequency response of a linear system.

Tips: corner frequency, slopes, and reading a Bode plot

Corner frequency: the point where the response transitions from one asymptote to another. At this frequency the actual curve is 3 dB below the asymptote for a first-order low-pass filter.

Slopes: first-order systems change at -20 dB/decade (magnitude) and -45 deg/decade (phase) through the corner. Second-order systems change at -40 dB/decade and -90 deg/decade.

Decade vs octave: a decade is a factor of 10 in frequency; an octave is a factor of 2. First-order slopes are -6 dB/octave, which equals -20 dB/decade.

Gain margin and phase margin: on a Bode plot of a control-system open-loop response, the gain margin is how many dB of gain you can add before instability, and the phase margin is how many degrees of phase lag you can add.

Always label your axes with units (Hz or rad/s for frequency, dB for magnitude, degrees for phase) so the plot is self-explanatory.

Frequently asked questions

A Bode plot generator is a tool that creates frequency response diagrams for electrical filters, amplifiers, and control systems. With Figviz you describe the system in plain text and the AI generates a labeled magnitude and phase plot with the corner frequency, slopes, and log-frequency axis, in seconds.

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