Two digits and a multiplier
For a common three-digit ceramic capacitor marking, the first two digits are the significant figures. The third digit is the power of ten that multiplies them, in picofarads. A marking of 104 means 10 × 10⁴ pF = 100,000 pF = 100 nF = 0.1 µF.
| Code | pF | nF | µF |
|---|---|---|---|
| 100 | 10 | 0.01 | 0.00001 |
| 101 | 100 | 0.1 | 0.0001 |
| 102 | 1,000 | 1 | 0.001 |
| 103 | 10,000 | 10 | 0.01 |
| 104 | 100,000 | 100 | 0.1 |
| 105 | 1,000,000 | 1,000 | 1 |
| 222 | 2,200 | 2.2 | 0.0022 |
| 472 | 4,700 | 4.7 | 0.0047 |
| 473 | 47,000 | 47 | 0.047 |
| 474 | 470,000 | 470 | 0.47 |
Worked tolerance examples
104K means a nominal 100 nF with a K tolerance of ±10%, giving a nominal tolerance range of 90 to 110 nF. A 473J marking means 47 nF with ±5%, or 44.65 to 49.35 nF. Tolerance alone does not account for changes caused by temperature, DC bias or aging.
| Letter | Common tolerance |
|---|---|
| J | ±5% |
| K | ±10% |
| M | ±20% |
What the code does not tell you
The capacitance code alone does not specify the voltage rating or dielectric. Manufacturer prefixes and extra letters vary. Read the part's datasheet before deciding whether it suits a circuit. Many small surface-mount capacitors have no printed marking at all.
For unit conversion, 1 nF = 1,000 pF and 1 µF = 1,000 nF. A number such as 100 can be ambiguous outside the three-digit convention, so check the marking scheme for that part.
Reference: KEMET radial ceramic capacitor datasheet and capacitance-code table.