How to use it
- Type the marking in Marking or value, for example 104K from the side of the part, or a value such as 100nF.
- Choose the Capacitor type: picofarads for most ceramic and film parts, microfarads for aluminium electrolytics.
- For a value, add the Tolerance you need or the Voltage of the part if you want the letter codes.
- Read Capacitance for a code, or Three-digit marking code for a value. Open Working, step by step for the reading.
How the three-digit code works
The first two digits are the significant figures and the third is a multiplier. The value is in picofarads for ceramic, film and tantalum parts and in microfarads for aluminium electrolytics. 104 means 10 followed by four zeros: 100 000 pF, which is 100 nF.
value = (first digit × 10 + second digit) × 10^(third digit)
104 → 10 × 10⁴ pF = 100 000 pF = 100 nF
221 → 22 × 10¹ pF = 220 pF
474 → 47 × 10⁴ pF = 470 000 pF = 470 nF- Values below 10 pF are marked in other ways, for example with a letter standing for the decimal point. This calculator covers the three-digit form only.
- The third digit can be 0 to 6 in the table used here. The codes 7 to 9 are not covered.
- Electrolytic capacitors are marked in microfarads, so 106 would mean 10 F; in practice their codes are written with the value and the voltage printed on the can.
Tolerance and voltage letters
The letter after the code gives the tolerance, from the EIA scheme. Surface-mount electrolytic and tantalum parts often have a letter for the voltage instead of a figure; the table below lists them.
| Tolerance letter | Tolerance |
|---|---|
| F | ±1 % |
| G | ±2 % |
| J | ±5 % |
| K | ±10 % |
| M | ±20 % |
| Z | +80 %, −20 % |
| D | ±0.5 % |
| C | ±0.25 % |
| B | ±0.1 % |
What this calculator does not cover
- Other marking systems, such as coloured bands on tubular capacitors, or the full IEC 60062 table of codes.
- Ratings that are not in the tables: the working voltage, temperature range and ripple current of a part come from its datasheet.
- Capacitors that are marked with their value in words, such as 1µ0 or 10n.
Worked example: 104K and 2.2 µF
The marking 104K gives 10 × 10⁴ pF = 100 000 pF = 100 nF with a tolerance of ±10 % (letter K).
A 2.2 µF ceramic capacitor is 2 200 000 pF = 22 × 10⁵ pF, so its code is 225. A 10 µF electrolytic has the code 100 in microfarads, and its 16 V rating shows as the letter C on an SMD part.
Frequently asked questions
What does 104 mean on a capacitor?
It means 10 × 10⁴ pF, which is 100 000 pF or 100 nF. The first two digits are the figures and the third is the number of zeros, in picofarads.
Why does 104K show ±10 %?
The letter K is the EIA tolerance code for ±10 %. The letters J, K and M mean ±5 %, ±10 % and ±20 %.
How do I read an electrolytic capacitor?
Choose Aluminium electrolytic: the three digits are then in microfarads, so 100 means 10 µF. Electrolytics usually print the value and voltage in full, so the code is mostly needed for SMD parts.
What is the voltage letter C?
On SMD electrolytic and tantalum parts, C stands for 16 V in the EIA table, along with e for 2.5 V, G for 4 V, J for 6.3 V, A for 10 V, D for 20 V, E for 25 V, V for 35 V and H for 50 V.
Why does my value have no exact code?
The three-digit code has only two significant figures. A value such as 1.23 nF has no exact code, so the nearest one, 122 (1.2 nF), is shown with a note.
Sources
- Electronics Notes: Deciphering Capacitor Markings & Codes (EIA tolerance and voltage letters)
- Wikipedia: Electronic color code (IEC 60062 marking rules)
Figures and text last checked on Tuesday, November 10, 2026.