Free Capacitor Code Calculator – Decode 3-Digit Codes

Turning a 3-Digit Capacitor Code into a Real Value

Small ceramic and film capacitors carry a short numeric code rather than a printed value, because there is simply no room for the full figure. This calculator translates that code into the capacitance you actually need. The rule for a 3-digit code is straightforward: the first two digits are the significant figures and the third digit tells you how many zeros to add — effectively a power-of-ten multiplier. The answer always comes out in picofarads (pF), which the tool then converts into the units your schematic uses. Working through the logic, a code with digits AB followed by multiplier C means the value is the number AB multiplied by ten raised to the power C, in picofarads. So code 104 is 10 followed by four zeros: 10 × 10⁴ = 100,000 pF. Because 1,000 pF make a nanofarad and 1,000 nF make a microfarad, that same value is 100 nF or 0.1 µF. The calculator shows all three at once so you can match whatever your parts list, schematic, or supplier uses without doing the conversions in your head. It also reads one- and two-digit codes directly as picofarads, since very small capacitors are marked that way. A couple of quick examples cement the pattern. Code 223 is 22 followed by three zeros, or 22 × 10³ = 22,000 pF, which is 22 nF or 0.022 µF. Code 471 is 47 followed by one zero, giving 470 pF. And the ever-present 104 is 0.1 µF, the classic decoupling capacitor you find scattered across almost every circuit board. Watch out for 100, which is 10 followed by zero zeros — just 10 pF — not one hundred of anything. Two more worth memorising: 102 is 10 × 10² = 1,000 pF, exactly 1 nF, and 105 is 10 × 10⁵ = 1,000,000 pF, a full 1 µF. Notice how a single digit change at the end shifts the value by a factor of ten, which is precisely why a quick check beats a confident guess. This is an everyday time-saver when populating a board, sorting a drawer of loose capacitors, or reading a schematic that lists values in a different unit from the markings. An optional tolerance-letter field decodes the accuracy grade that often follows the number. Picture three real moments. Someone assembling an Arduino shield from a kit is told to fit a 0.1 µF decoupling capacitor and has to work out that the parts bag marked 104 is the right one. A repair enthusiast replacing a failed timing capacitor reads 223 off the old part, recognises 22 nF, and orders a match even though the supplier lists it as 0.022 µF. A guitar-pedal builder following a schematic that calls for 470 pF finds a capacitor marked 471 in the drawer and confirms they are the same part before soldering. In each case the code and the schematic use different units, and that mismatch is the whole problem this solves. Tolerance letters use the EIA standard: J is ±5 percent, K is ±10 percent, and M is ±20 percent are the common ones, with tighter grades like F (±1 percent) and G (±2 percent), and Z meaning +80/−20 percent on high-value ceramics. Type the letter after the code, such as 104K, or pick it from the list. One pitfall to remember: a capacitor already printed with a plain decimal like 0.1 or a notation like 4n7 is showing its value directly and needs no decoding, and electrolytics usually print the µF value and voltage outright. The bigger trap is what the code does not tell you: the voltage rating. A 104 marked for 50 volts and a 104 marked for 630 volts decode to the identical 0.1 µF, but fitting the 50-volt part where the 630-volt one belonged will end in a bang. Always check the voltage rating printed alongside or in the datasheet, and pick a part rated well above your circuit's working voltage. Tolerance matters too — a 104K is only promised to fall between 0.09 and 0.11 µF, which is fine for decoupling but not for a precision filter. Where the capacitor sits in mains-connected equipment, follow local electrical code and let a qualified electrician handle that work. All decoding runs locally in your browser, so nothing you enter is uploaded.

Capacitor Code Calculator Formula & Method

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