Tools/RC Time Constant Calculator

RC Time Constant Calculator

Calculate timing, cutoff frequency, and charge curves

RC Circuit Parameters

Calculate

Resistance (kΩ)

Capacitance (μF)

Target Charge Level (%)

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

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

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).

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