Electronics · Capacitors
Capacitor code calculator.
Type the number printed on a small capacitor, such as 104 or 473K, to get picofarads, nanofarads and microfarads.
Inputs
Result
Enter a code.
How to read a capacitor code
The first two digits are the value and the third digit is how many zeros follow, in picofarads. So 104 is 10 followed by four zeros, 100,000 pF, which is 100 nF or 0.1 µF. A letter after the digits is the tolerance: J is ±5%, K is ±10% and M is ±20%.
Worked example. Wikipedia's example is 473K: 47 × 103 pF = 47 nF, ±10%. Other common codes: 102 = 1 nF, 103 = 10 nF, 104 = 100 nF, 224 = 220 nF, 105 = 1 µF.
Conversions. 1,000 pF = 1 nF and 1,000 nF = 1 µF. So 100,000 pF = 100 nF = 0.1 µF.
Limits of this tool. Multiplier digits 7 to 9 are refused: some makers use 8 and 9 for decimals (such as 109 for 1.0 pF), which the source here does not cover, so check the datasheet. Other tolerance letters exist (for example for small picofarad parts); only J, K and M are decoded. A voltage rating printed beside the code, such as 330V, is a separate marking.
Frequently asked questions
What is a 104 capacitor?
104 means 10 followed by four zeros in picofarads: 100,000 pF = 100 nF = 0.1 µF.
What is a 473 capacitor?
473 is 47 followed by three zeros: 47,000 pF = 47 nF = 0.047 µF.
What do the letters J, K and M mean?
They give tolerance: J is ±5%, K is ±10% and M is ±20%.
How do I convert 224 to microfarads?
224 = 22 × 10^4 pF = 220,000 pF = 220 nF = 0.22 µF.
Does the code tell me the voltage rating?
No. The code gives capacitance (and sometimes tolerance). The working voltage is printed separately, and it should be above the voltage in your circuit.
Sources
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Scope and safety
Low-voltage hobby use only. These results are arithmetic from the formulas shown, not an engineering design or professional advice. Real parts vary with tolerance, temperature and age, so check the datasheet for every part. Never work on mains-powered circuits from a calculator result, and treat lithium and other rechargeable batteries with care. The rule here is the one stated for small capacitors on Wikipedia; read the maker's datasheet for exceptions.