RC & RLC Filter Calculator | Cutoff Frequency & Bode Plot

Accurate tool for designing RC Low Pass, RC High Pass, and RLC Band Pass filters. Calculate the Cutoff Frequency, Time Constant, and Q-Factor while visualizing the signal attenuation with a real-time Bode Plot.

Configuration

Input

Filter Topology

Resistance (R)

Capacitance (C)

Analysis

Result

Cutoff Frequency (f_c)

— Hz

Phase @ f_c: — τ: —

Frequency Response (Bode Plot)

Common Questions & Physics

What is Cutoff Frequency (f_c)?

The frequency where the output power drops by half (-3dB). At this point, the output voltage is 70.7% of the input voltage.

Time Constant (τ)

In RC circuits, τ = R×C. It represents the time required to charge the capacitor to 63.2% of its full capacity.

Phase Shift

Filters introduce a delay. At the cutoff frequency, a simple RC filter creates a 45° phase shift between input and output.

How to Use

Select Topology

Choose Low Pass, High Pass, or Band Pass from the configuration menu to set the circuit type.

Input Components

Enter your Resistance (R) and Capacitance (C). For Band Pass filters, also provide the Inductance (L).

Analyze Results

Observe the calculated Cutoff Frequency and use the interactive Bode Plot to visualize signal attenuation.