The SI unit of Capacitance is the Farad (abbreviated as F). it was named after the British physicist Michael Faraday and is defined as:-
“Capacitor has the capacitance of One Farad when a charge of One Coulomb is stored on the plates by a voltage of One volt”
Capacitance C is always positive and has no negative units. However, the Farad is a very large unit of measurement to use on its own so sub-multiples of the Farad is generally used such as micro-farads, nano-farads and pico-farads, for example.
Prefixes Used For Ohms
Microfarad (μF) 1μF = 1/1,000,000 = 0.000001 = 10-6 F
Nanofarad (nF) 1nF = 1/1,000,000,000 = 0.000000001 = 10-9 F
Picofarad (pF) 1pF = 1/1,000,000,000,000 = 0.000000000001 = 10-12 F