Capacitor Code Decoder

About this tool

Decodes the short printed marking on a ceramic, film, or tantalum capacitor into an actual capacitance value, shown in pF, nF and µF at once. It handles the four notations you'll meet on real parts.

1. The 3-digit EIA code (e.g. 104). The first two digits are significant figures; the third is the number of zeros to append, and the whole thing is in picofarads. 104 = 10, then 4 zeros = 100,000 pF = 100 nF = 0.1 µF. 223 = 22,000 pF = 22 nF. A third digit of 0 means "no zeros": 100 = 10 pF, not 100.

2. Letter-as-decimal shorthand (e.g. 4n7, 2p2, 1µ5). The unit letter sits where the decimal point would go. 4n7 = 4.7 nF, 2p2 = 2.2 pF, 1µ5 = 1.5 µF. This style is unambiguous and common on European film capacitors.

3. Plain small values (e.g. 22, 4.7). A bare 1–2 digit number with no multiplier is just picofarads: 22 = 22 pF.

4. The tolerance letter (e.g. the K in 473K). A trailing letter gives how far the real value may stray from the marked one:

So 473K is 47,000 pF = 47 nF at ±10%.

A voltage or temperature-coefficient code (like 2A for 100 V, or X7R, C0G/NP0 for the dielectric class) is sometimes printed alongside. This tool reads the capacitance and tolerance; the dielectric class affects stability and is worth checking on the datasheet for anything precision.

Why not just print the value? On a component a few millimetres wide there's no room for "0.047 µF ±10%". The code is a compact, unambiguous shorthand once you know the rule.

For resistors, the equivalent tool is the resistor color code. To use the capacitor in a timing circuit, see the RC time constant calculator; with an inductor, the inductor color code.

Frequently asked questions

How does the 3-digit code work?

First two digits are significant figures, the third is how many zeros to add, all in picofarads. 104 = 10 followed by 4 zeros = 100,000 pF = 100 nF = 0.1 µF.

What does the letter at the end mean?

Tolerance. J = ±5%, K = ±10%, M = ±20%, and so on — the capacitor version of a resistor's tolerance band.

What's the difference between "4n7" and "104"?

Both are notations for a capacitance. 4n7 directly means 4.7 nF (the letter is the decimal point). 104 is the EIA code: two digits plus a zero-count multiplier.

Does a third digit of 0 mean multiply by 1?

Yes. 100 is 10 pF (10 with no zeros added), not 100 pF. 101 is 100 pF.

What about the voltage rating?

That's a separate code (often a digit-letter pair) and isn't decoded here. Check the datasheet, and never exceed it in circuit.

My marking has three letters like X7R — what's that?

The dielectric class, which describes temperature stability rather than capacitance. C0G/NP0 is the most stable; X7R and Y5V drift more with temperature and voltage.