Capacitance

Capacitance is how much electric charge a component stores for each volt across it. It is measured in farads (F), and most real capacitors are rated in microfarads (µF) or smaller.

Capacitance sets how long a capacitor takes to charge. Multiply it by resistance to get the RC time constant: 100 µF, which is 0.0001 F, times 10 kΩ gives 1 second. With a constant current, charge time is C x ΔV / I.

Stored energy is ½CV², so energy grows with the square of voltage. The capacitor charging time calculator takes capacitance in any common unit, and the FAQ on how long a capacitor takes to charge has a worked example.