How to read a capacitor code
Small ceramic and film capacitors have no room for “100 nF”, so they carry a three-digit code in picofarads: the first two digits are the value and the third is how many zeros follow.
104 → 10 and 0000 = 100 000 pF = 100 nF = 0.1 µF 473 → 47 and 000 = 47 000 pF = 47 nF 221 → 22 and 0 = 220 pF
Below 10 pF the third digit becomes a multiplier below one: 9 means × 0.1 and 8 means × 0.01, so 229 is 2.2 pF and 508 is 0.5 pF. Another system, from IEC 60062, puts the unit letter where the decimal point goes: 4n7 is 4.7 nF, p47 is 0.47 pF and 2u2 is 2.2 µF.
Common codes
| Code | pF | nF | µF |
|---|---|---|---|
| 100 | 10 | 0.01 | 0.00001 |
| 101 | 100 | 0.1 | 0.0001 |
| 221 | 220 | 0.22 | 0.00022 |
| 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 |
Tolerance letters
A letter right after the code is the tolerance: 104K is 100 nF ± 10 %. B, C, D, F and G are in picofarads on values below 10 pF and in percent above.
| Letter | Tolerance |
|---|---|
| B | ± 0.1 pF · ± 0.1 % |
| C | ± 0.25 pF · ± 0.3 % |
| D | ± 0.5 pF · ± 0.5 % |
| F | ± 1 pF · ± 1 % |
| G | ± 2 pF · ± 2 % |
| J | ± 5 % |
| K | ± 10 % |
| M | ± 20 % |
| Z | +80 / −20 % |
Voltage codes
Film capacitors and some ceramics put a digit and a letter in front of the code for the rated voltage. The digit is a power of ten and the letter the leading figure: 2A is 1.0 × 10² = 100 V and 1H is 5.0 × 10 = 50 V.
| Code | Rated voltage |
|---|---|
| 0J | 6.3 V |
| 1A | 10 V |
| 1C | 16 V |
| 1E | 25 V |
| 1V | 35 V |
| 1H | 50 V |
| 1J | 63 V |
| 2A | 100 V |
| 2D | 200 V |
| 2E | 250 V |
| 2G | 400 V |
| 2W | 450 V |
| 2J | 630 V |
| 3A | 1,000 V |
Ceramic dielectric codes
A class 2 code such as X7R gives the lowest working temperature (X = −55 °C, Y = −30 °C, Z = +10 °C), the highest (5 = +85 °C, 6 = +105 °C, 7 = +125 °C) and the largest capacitance change across that range (R = ± 15 %, S = ± 22 %, U = +22 / −56 %, V = +22 / −82 %). Class 2 ceramics also lose capacitance as the DC voltage rises and as they age. C0G, also called NP0, is class 1: almost no change with temperature, voltage or time, which is why it goes in filters and oscillators.
| Code | Temperature range | Capacitance change |
|---|---|---|
| C0G (NP0) | −55 … +125 °C | 0 ± 30 ppm/°C |
| X7R | −55 … +125 °C | ±15 % |
| X5R | −55 … +85 °C | ±15 % |
| X6S | −55 … +105 °C | ±22 % |
| X7S | −55 … +125 °C | ±22 % |
| X8R | −55 … +150 °C | ±15 % |
| Y5V | −30 … +85 °C | +22 / −82 % |
| Z5U | +10 … +85 °C | +22 / −56 % |
Sources: capacitor makers’ marking and ordering guides (KEMET, AVX, Vishay, Nichicon), which follow EIA-198 and IEC 60062.
Frequently asked questions
What does 104 mean on a capacitor?
100 nF, that is 0.1 µF or 100 000 pF: 10 followed by four zeros, in picofarads. It is the usual decoupling capacitor next to chips.
What is a 473J capacitor?
47 nF (47 000 pF, 0.047 µF) with a tolerance of ± 5 %, which is what the J stands for.
What does 2A104J mean?
Rated for 100 V (2A), 100 nF (104), ± 5 % (J): a typical marking on polyester film capacitors.
Is 100 on a capacitor 10 pF or 100 pF?
As a three-digit code it is 10 pF: 10 followed by no zeros. Some makers of small ceramic discs print the value written out instead, and then 100 means 100 pF. If the circuit doesn’t make it clear, measure it.
What does X7R mean?
A class 2 ceramic that stays within ± 15 % of its value from −55 to +125 °C. X5R is the same up to +85 °C. Y5V and Z5U change much more (down to −82 % and −56 %) and are best avoided where the value matters.
How many nF is 1 µF?
1 µF = 1000 nF = 1 000 000 pF. To go from nF to µF divide by 1000: 100 nF = 0.1 µF and 4.7 nF = 0.0047 µF.