Quick answer
The first two digits are the value and the third is the number of zeros, in picofarads. 104 = 100,000 pF = 100 nF = 0.1 µF. 103 = 10 nF, 102 = 1 nF.
How to use the Capacitor Code Calculator
- Find the code printed on the capacitor, for example
104or473J. - Type it into the field, including any letter at the end. The value appears instantly.
- To find the code for a value, open Value → code and enter the capacitance.
Example
A small yellow ceramic capacitor is marked 104K:
- First two digits:
10 - Third digit = number of zeros:
4→ 10 0000 pF = 100,000 pF - 100,000 pF = 100 nF = 0.1 µF
- K = ±10% tolerance
Other common codes: 102 = 1 nF, 103 = 10 nF, 222 = 2.2 nF, 473 = 47 nF, 105 = 1 µF.
How it works
Small capacitors use the EIA 3-digit code, always in picofarads (pF). The first two digits are the significant figures and the third is the multiplier (number of zeros). A third digit of 8 means ×0.01 and 9 means ×0.1.
Other common markings:
- R as a decimal point:
4R7= 4.7 pF - Unit letter as decimal point:
4n7= 4.7 nF,2u2= 2.2 µF,1p5= 1.5 pF - One or two digits only: the value in pF, e.g.
47= 47 pF - Decimals: values like
.1or0.22on film capacitors are in µF
| Letter | Tolerance | Letter | Tolerance |
|---|---|---|---|
| B | ±0.1 pF | G | ±2% |
| C | ±0.25 pF | J | ±5% |
| D | ±0.5 pF | K | ±10% |
| F | ±1% | M | ±20% |
| Z | +80% / −20% |
1 µF = 1,000 nF = 1,000,000 pF.
Quick reference: the codes you'll see most
- 104 (100 nF): the standard decoupling capacitor placed next to almost every chip.
- 103 (10 nF) and 102 (1 nF): common in filters and timing circuits.
- 22 or 220 (22 pF): often found in pairs next to microcontroller crystals.
- 105 (1 µF) and 106 (10 µF): larger ceramic capacitors, often for power supply filtering.
- Replacing a capacitor: match the capacitance, and choose a voltage rating at least equal to the original, ideally higher.
Frequently asked questions
What is a 104 capacitor?
104 means 10 followed by 4 zeros in picofarads: 100,000 pF, which is 100 nF or 0.1 µF. It's the most common decoupling capacitor in electronics.
What does 103 mean on a capacitor?
10 followed by 3 zeros: 10,000 pF = 10 nF = 0.01 µF.
What is the difference between pF, nF and µF?
They are steps of 1,000: 1 nF = 1,000 pF and 1 µF = 1,000 nF. Small ceramic capacitors are usually in pF or nF; electrolytic capacitors in µF.
Is the voltage rating part of the code?
Sometimes a separate marking shows the voltage, such as 50V or a code like 1H (50 V) or 2A (100 V). Always choose a capacitor rated above your circuit voltage.
Why don't electrolytic capacitors use this code?
Electrolytic capacitors are larger, so their value and voltage are printed directly, for example 470µF 25V.