Our calculator assumes that a capacitor is being charged, and inspection of the equation used will show that when T=RC, the voltage will have risen to 63.21% of its final value. However, it is easy to transfer the answer to a discharging capacitor: when T=RC, the voltage will have lost 63.21% of its initial value (or will retain 36.79% of its initial value).

The multipliers available for the input of known values range from µ to M ... that is from micro- through milli- and Kilo- to Mega-. It is not compulsory to use the available multipliers correctly, eg 0.5S or 500mS are both acceptable. The default multiplier for T and R is 1; for C , it is µ.

For your convenience, answers for T, R & C are shown in standard engineering multipliers ranging from one pico-unit (10^-12) to one Tera-unit (10^+12). Results outside this range will not be shown! Results for percentage are always shown as percentages (without multipliers).