How to read a capacitor code
Small capacitors have no room for “100 nF”, so they carry a three-digit code in picofarads (pF). The first two digits are the value and the third is the number of zeros to add.
104 is 10 followed by four zeros: 100,000 pF, which is 100 nF or 0.1 µF. 472 is 4,700 pF, or 4.7 nF. A third digit of 9 or 8 means ×0.1 or ×0.01, so 109 is 1 pF.
Below 10 pF the letter R marks the decimal point: 4R7 is 4.7 pF. Values from 10 to 99 pF are often printed with just two digits, so 22 and 220 both mean 22 pF.
A letter after the digits is the tolerance, as in 104K (±10%). A digit and a letter in front, as in 2A104J, is the rated voltage: 2A is 100 V. Aluminum electrolytic capacitors usually have the value and voltage printed in full, such as 470 µF 25 V. SMD ceramic capacitors often have no marking at all, so you have to measure them.
Common capacitor codes
| Code | pF | nF | µF |
|---|---|---|---|
| 100 | 10 | 0.01 | 0.00001 |
| 220 | 22 | 0.022 | 0.000022 |
| 101 | 100 | 0.1 | 0.0001 |
| 471 | 470 | 0.47 | 0.00047 |
| 102 | 1,000 | 1 | 0.001 |
| 222 | 2,200 | 2.2 | 0.0022 |
| 472 | 4,700 | 4.7 | 0.0047 |
| 103 | 10,000 | 10 | 0.01 |
| 223 | 22,000 | 22 | 0.022 |
| 473 | 47,000 | 47 | 0.047 |
| 104 | 100,000 | 100 | 0.1 |
| 224 | 220,000 | 220 | 0.22 |
| 474 | 470,000 | 470 | 0.47 |
| 105 | 1,000,000 | 1,000 | 1 |
| 106 | 10,000,000 | 10,000 | 10 |
| 107 | 100,000,000 | 100,000 | 100 |
Tolerance letters
| Letter | Tolerance |
|---|---|
| B | ±0.1 pF |
| C | ±0.25 pF |
| D | ±0.5 pF below 10 pF, otherwise ±0.5% |
| F | ±1% |
| G | ±2% |
| J | ±5% |
| K | ±10% |
| M | ±20% |
| Z | +80% / −20% |
Voltage codes
The voltage code is a digit and a letter printed before the value, mostly on film capacitors.
| Code | Voltage | Code | Voltage |
|---|---|---|---|
| 0G | 4 V | 2C | 160 V |
| 0J | 6.3 V | 2D | 200 V |
| 1A | 10 V | 2E | 250 V |
| 1C | 16 V | 2F | 315 V |
| 1E | 25 V | 2V | 350 V |
| 1V | 35 V | 2G | 400 V |
| 1H | 50 V | 2W | 450 V |
| 1J | 63 V | 2H | 500 V |
| 1K | 80 V | 2J | 630 V |
| 2A | 100 V | 3A | 1000 V |
Frequently asked questions
What is a 104 capacitor?
A 104 capacitor is 100 nF, the same as 0.1 µF or 100,000 pF. It’s the most common decoupling capacitor, placed next to the power pins of almost every chip.
Can I use a 0.1 µF capacitor in place of a 100 nF one?
Yes. 0.1 µF and 100 nF are the same value written in different units. Check that the voltage rating is at least as high as the original.
What does the K in 104K mean?
K is the tolerance, ±10%, so a 104K capacitor can be anywhere from 90 nF to 110 nF. J is ±5% and M is ±20%.
Why is my value not exact?
A code has only two significant digits, so 4.75 nF can’t be written exactly. The calculator picks the closest code (482, 4.8 nF) and tells you it rounded.