Is this calculation free and private?

Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.

What does the RC Low-Pass Filter Cutoff Frequency Calculator give me?

It works out Cutoff Frequency -3dB, Time Constant τ, Attenuation at Test Freq and Phase Shift Angle, updating live as you change the inputs.

What do I need to enter?

Just Resistance R, Capacitance C and Signal Test Frequency. Every field has a sensible default you can start from.

Is my data uploaded anywhere?

No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.

Does it work on a phone?

Yes. The layout adapts to small screens and needs no app or signup.

RC Low-Pass Filter Cutoff Frequency Calculator

Calculate -3dB cutoff frequency (fc), time constant (τ), and phase angle for passive analog RC low-pass and audio tone filters.

100% free
Private in browser
No signup
No watermarks

Resistance R (Ohms Ω)

Capacitance C (Microfarads µF)

Signal Test Frequency (Hz)

Cutoff Frequency -3dB (Hz)

159.2

Time Constant τ (Milliseconds)

Attenuation at Test Freq (dB)

-16.1

Phase Shift Angle (°)

-81

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About RC Low-Pass Filter Cutoff Frequency Calculator

Calculate -3dB cutoff frequency (fc), time constant (τ), and phase angle for passive analog RC low-pass and audio tone filters. Enter Resistance R, Capacitance C and Signal Test Frequency and the tool works out Cutoff Frequency -3dB, Time Constant τ and Attenuation at Test Freq straight away. Everything runs in your browser, so your data never leaves your device.

How to use RC Low-Pass Filter Cutoff Frequency Calculator

Enter Resistance R, Capacitance C and Signal Test Frequency.
Change any value to see the result update instantly.
Read Cutoff Frequency -3dB, Time Constant τ and Attenuation at Test Freq in the results panel — copy or download what you need.

Key features

Shows Cutoff Frequency -3dB (Hz)
Shows Time Constant τ (Milliseconds)
Shows Attenuation at Test Freq (dB)
3 adjustable inputs, results update as you type
No signup, no limits

Frequently asked questions

Is this calculation free and private?: Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.
What does the RC Low-Pass Filter Cutoff Frequency Calculator give me?: It works out Cutoff Frequency -3dB, Time Constant τ, Attenuation at Test Freq and Phase Shift Angle, updating live as you change the inputs.
What do I need to enter?: Just Resistance R, Capacitance C and Signal Test Frequency. Every field has a sensible default you can start from.
Is my data uploaded anywhere?: No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.
Does it work on a phone?: Yes. The layout adapts to small screens and needs no app or signup.

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