RC Filter Cutoff Calculator
Calculate the -3 dB cutoff frequency of a simple RC low-pass or high-pass filter.
Ω
nF
Cutoff Frequency
1,591.5 Hz
Time Constant (RC)0.1000 ms
Cutoff Frequency vs Resistance
RC Filter Cutoff
f_c = 1 / (2 x pi x R x C)
At the cutoff frequency, output is -3 dB (70.7%) of the input. The time constant tau = RC.
Example Calculation
R = 1k, C = 100 nF.
- 01C = 100 nF = 1e-7 F
- 02f_c = 1 / (2pi x 1000 x 1e-7) = 1591.5 Hz
- 03tau = 1000 x 1e-7 = 0.1 ms
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