Reading capacitor codes
Small ceramic and film capacitors have no room for "100 nF", so they use a three-digit code in picofarads: the first two digits are the value and the third is the number of zeros. 104 is 10 followed by 4 zeros = 100,000 pF = 100 nF = 0.1 µF, the most common decoupling capacitor in electronics.
A letter after the code gives the tolerance: J ±5%, K ±10%, M ±20%, Z +80/−20%. Film capacitors often add the voltage: 223J 100V is 22 nF, ±5%, rated for 100 V.
Other notations put a letter where the decimal point goes: 4n7 = 4.7 nF, 2u2 = 2.2 µF, 3p3 = 3.3 pF. Two digits alone, like 22, are simply 22 pF.
Worked example
473K: 47 × 10³ pF = 47,000 pF = 47 nF = 0.047 µF, tolerance ±10%.
How this works
The page reads the code in the order IEC 60062 defines: a value part (three digits with a multiplier, two digits in pF, or digits around a p, n, u or R decimal letter), then an optional tolerance letter and an optional voltage ending in V. The value is converted to picofarads and shown in pF, nF and µF together, and the tolerance letter is translated using the IEC table. Everything runs in your browser.
Frequently asked
What does 104 mean on a capacitor?
10 followed by 4 zeros, in picofarads: 100,000 pF = 100 nF = 0.1 µF.
What does the K in 104K mean?
The tolerance: K is ±10%. J is ±5% and M is ±20%.
Is 0.1 µF the same as 100 nF?
Yes. 1 µF = 1,000 nF = 1,000,000 pF.
How do I read 4n7?
n marks the decimal point in nanofarads: 4.7 nF.
Sources
Reviewed Oct 17, 2026 · test vectors fixtures/codes/capacitor-code/