This calculator converts the 3 digit codes and alphabetical tolerance codes which are found on small capacitors.
Capacitance =
Tolerance =
How the code works
Ceramic and film capacitors are usually too small to print a full value on, so many carry a three-digit code instead. It works the same way as the surface mount resistor code: the first two digits are the significant figures, and the third is the multiplier, the number of zeros to add. The result is in picofarads (pF).
So 104 is 10 followed by four zeros: 100,000 pF, which is 100 nF or 0.1 µF. Likewise 220 is 22 pF (a trailing zero means a multiplier of one, not an extra zero), and 473 is 47,000 pF, or 47 nF.
A letter after the digits gives the tolerance, how far the real value may stray from the marked one. J is ±5%, K is ±10% and M is ±20% are the ones you'll meet most often.
Capacitor conversion table
Capacitor values are quoted in picofarads (pF), nanofarads (nF) or microfarads (µF) depending on the size, and it's easy to lose track of a factor of a thousand between them. This table lines them up:
| Picofarads (pF) | Nanofarads (nF) | Microfarads (µF) |
|---|---|---|
| 1 | 0.001 | 0.000001 |
| 10 | 0.01 | 0.00001 |
| 100 | 0.1 | 0.0001 |
| 1000 | 1 | 0.001 |
| 10000 | 10 | 0.01 |
| 100000 | 100 | 0.1 |
| 1000000 | 1000 | 1 |
| 10000000 | 10000 | 10 |
