Capacitor Code Calculator
Decode ceramic and film capacitor markings such as 104, 473J, 4R7 or 2n2 into pF, nF and µF with the tolerance letter — or turn a capacitance into its 3-digit capacitor code.
How it works
3-digit code AB C → AB × 10^C pF (104 = 10 × 10⁴ pF = 100 nF = 0.1 µF) · third digit 8 → ×0.01, 9 → ×0.1 · 1–2 digits = pF · R / p / n / µ mark the decimal point (4R7 = 4.7 pF, 2n2 = 2.2 nF) · tolerance letter: B ±0.1 pF, C ±0.25 pF, D ±0.5 pF, F ±1%, G ±2%, J ±5%, K ±10%, M ±20%, Z +80/−20%
Small ceramic, film and tantalum capacitors are marked with the EIA/IEC 60062 code: two significant digits and a multiplier giving the value in picofarads, often followed by a tolerance letter. Larger or newer parts may print the value directly with the unit letter as the decimal point (2n2, 4µ7). Remember that 1 µF = 1,000 nF = 1,000,000 pF — schematics and shops often use different units for the same part, which is why the calculator shows all three.
Worked example
A ceramic capacitor marked 104K: 10 × 10⁴ = 100,000 pF = 100 nF = 0.1 µF, and K means ±10%, so the real value lies between 90 nF and 110 nF. Going the other way, 100 nF is written 104.
Sources: IEC 60062:2016 Marking codes for resistors and capacitors · Capacitor — markings (Wikipedia)
Frequently asked questions
What does 104 mean on a capacitor?
10 followed by four zeros picofarads: 100,000 pF = 100 nF = 0.1 µF. It is the most common decoupling capacitor value. Likewise 103 = 10 nF, 102 = 1 nF, 105 = 1 µF and 474 = 470 nF.
What do the letters J, K and M after the code mean?
Tolerance: J = ±5%, K = ±10%, M = ±20%. For small values under 10 pF absolute tolerances are used instead: B ±0.1 pF, C ±0.25 pF, D ±0.5 pF. Z means +80% / −20%, typical of cheap Y5V/Z5U ceramics.
Is a capacitor marked 47 or 470 different?
Yes. One or two digits give the value directly in pF (47 = 47 pF), while three digits use the multiplier rule (470 = 47 × 10⁰ = 47 pF too, but 471 = 470 pF). Always check whether the third digit is a multiplier.
How is a capacitor’s voltage marked?
Often by a separate code such as 1H (50 V), 2A (100 V) or 2J (630 V) on film capacitors, or simply printed (50V). This calculator decodes the capacitance and tolerance; check the datasheet or the separate voltage code for the rating.
Why does an electrolytic capacitor not use this code?
Electrolytics are large enough to print the value and voltage in full (e.g. 470 µF 25 V) along with a stripe marking the negative lead. The 3-digit code is used on small ceramic, film, mica and SMD tantalum parts.
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This calculator is for educational purposes. Double-check important results before acting on them.