Capacitor codes.
Type the number printed on the cap (104, 473J, 4n7) and get the value in pF, nF and µF. Or work backwards from a value to its code.
1–2 digits: the value in pF as printed. R / p, n or u in place of a decimal point: pF, nF or µF.
A trailing letter is the tolerance (see the table below).
→ —
Common capacitor codes
Two digits, then zeros
The first two digits are the value; the third says how many zeros follow. 473 is 47 and three zeros.
Always picofarads
The answer is in pF. Divide by 1,000 for nF and by 1,000,000 for µF: 47,000 pF = 47 nF = 0.047 µF.
A letter is tolerance
J, K and M after the code mean ±5%, ±10% and ±20%. The letter is not part of the value.
| CODE | pF | nF | µF |
|---|---|---|---|
| 100 | 10 | 0.01 | 0.00001 |
| 220 | 22 | 0.022 | 0.000022 |
| 470 | 47 | 0.047 | 0.000047 |
| 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 |
| 225 | 2,200,000 | 2,200 | 2.2 |
| 475 | 4,700,000 | 4,700 | 4.7 |
| LETTER | TOLERANCE | TYPICAL ON |
|---|---|---|
| B | ±0.1 pF | small (under 10 pF) C0G/NP0 parts |
| C | ±0.25 pF | small (under 10 pF) C0G/NP0 parts |
| D | ±0.5 pF | small (under 10 pF) C0G/NP0 parts |
| F | ±1% | precision film and C0G |
| G | ±2% | precision film and C0G |
| J | ±5% | film and C0G ceramic |
| K | ±10% | X7R ceramic, film |
| M | ±20% | general-purpose ceramic |
| Z | +80% / −20% | Y5V / Z5U decoupling ceramics |
Related reading: Decoding capacitor markings (104 is not 104 farads) →
Why 104 isn't 104 farads
Small ceramic and film capacitors don't have room for "100 nF", so they carry a three-digit EIA code instead. The first two digits are the significant figures, the third is how many zeros to add, and the answer is always in picofarads. The third digit only runs 0 to 6 for zeros; 8 means ×0.01 and 9 means ×0.1, for values under 10 pF.
So 104 is 10 × 10⁴ = 100,000 pF, which is 100 nF or
0.1 µF. Read it as 104 farads and you'd be expecting a supercapacitor the size of a
battery, not a blue blob the size of a lentil.
Example. A yellow film cap reads 473J. The digits are 47,
the 3 adds three zeros: 47,000 pF = 47 nF = 0.047 µF. The J is the tolerance
letter, ±5%, so the real part sits anywhere from 44.65 nF to 49.35 nF.
Some parts skip the code: a lone 47 (one or two digits) is just 47 pF,
and a letter in the middle is the decimal point and the unit at once:
4R7 = 4.7 pF, n47 = 0.47 nF, 4n7 =
4.7 nF and 2u2 = 2.2 µF.
Gotcha: electrolytics don't use the code. Aluminium electrolytic cans
print the real value and voltage, e.g. 100µF 25V, plus a stripe marking the
negative lead. If a can says 100, it means 100 µF, not 10 pF. The
three-digit code is for the small stuff, and it is always picofarads; a 101
is 100 pF, not 101 of anything.
Questions people actually ask
What does 104 mean on a capacitor?
It is 10 followed by four zeros, in picofarads: 100,000 pF, which is 100 nF or 0.1 µF. It is the most common decoupling capacitor value on a board.
What does 103, 473 or 222 mean on a capacitor?
Take the first two digits and add the number of zeros given by the third, in picofarads. 103 is 10,000 pF (10 nF), 473 is 47,000 pF (47 nF) and 222 is 2,200 pF (2.2 nF).
What is the K or J after the capacitor code?
It is the tolerance letter, not part of the value. J is ±5%, K is ±10% and M is ±20%, so 104K is 100 nF ±10%, anywhere from 90 nF to 110 nF. Small parts can use B, C or D (±0.1, ±0.25 or ±0.5 pF), and Z means +80% / −20%.
What does 4R7 or n47 mean on a capacitor?
The letter is the decimal point and tells you the unit. R (or p) means picofarads, so 4R7 is 4.7 pF. n means nanofarads, so n47 is 0.47 nF (470 pF) and 4n7 is 4.7 nF. u means microfarads, so 2u2 is 2.2 µF.
How do I find the code for 100 nF?
Convert to picofarads first: 100 nF is 100,000 pF, which is 10 followed by four zeros, so the code is 104. Likewise 4.7 µF is 4,700,000 pF, 47 followed by five zeros, which is 475.
Are the numbers on electrolytic capacitors a code?
No. Electrolytic capacitors are big enough to print the value and voltage directly, for example 100µF 25V, usually with a stripe marking the negative lead. The three-digit code is used on small ceramic and film capacitors.