Time Constant: $\tau = R \times C$

Charging Voltage: $V_c(t) = V_s \times (1 - e^{-t/\tau})$

Discharging Voltage: $V_c(t) = V_0 \times e^{-t/\tau}$

Cutoff Frequency: $f_c = \frac{1}{2 \pi R C}$

A capacitor is considered fully charged (~99.3%) after $5\tau$.