RC Time Constant Calculator
Calculate timing, cutoff frequency, and charge curves
RC Circuit Parameters
Results
Time Constant (τ = RC)
1000.00 ms
Cutoff Frequency
0.16 Hz
Rise Time (10-90%)
2.197 s
Time to 63.2%
999.67 ms
τ × 5 (99.3%)
5.000 s
Charge/Discharge Curve
Time Constants
1τ
2τ
3τ
4τ
5τ
Charge Level
63.2%
86.5%
95%
98.2%
99.3%
Time
1000.00 ms
2.000 s
3.000 s
4.000 s
5.000 s
Common RC Applications
Low-Pass Filter
- • Attenuates frequencies above fc
- • -3dB at cutoff frequency
- • -20dB/decade rolloff
- • Used for noise filtering, audio
Timing Circuits
- • Delay circuits (t = τ × ln(V0/Vth))
- • Debouncing switches
- • Power-on reset circuits
- • 555 timer RC oscillators
One time constant (τ) charges the capacitor to 63.2% of the input voltage. Approximately 5τ is needed to reach 99.3% (practically fully charged).