How to use the capacitor code calculator
- Type the code printed on the capacitor, such as 104. Put one code on each line to decode several at once.
- Add a tolerance letter after the digits if one is printed, for example 104K.
- For small values marked with an R, such as 4R7, type the code as printed. The R stands for a decimal point.
- Read the value in picofarads, nanofarads and microfarads, along with the tolerance.
Formula
value in pF = first two digits x 10 to the power of the third digit
third digit 8 means x 0.01 and 9 means x 0.1
1,000 pF = 1 nF and 1,000,000 pF = 1 uF
The first two digits are the value and the third digit is the number of zeros, so the result is in picofarads. A letter after the digits is the tolerance, and an R in place of a digit is a decimal point.
The common code 104
Code 104 is 10 followed by 4 zeros, which is 100,000 pF. Dividing by 1,000 gives 100 nF, and dividing by 1,000,000 gives 0.1 uF.
The code 222K is 22 followed by 2 zeros, or 2,200 pF (2.2 nF), with a tolerance of 10 percent. The code 105J is 1,000,000 pF, which is 1 uF, at 5 percent. The R code 4R7 is 4.7 pF, and 479 is also 4.7 pF because the third digit 9 means multiply by 0.1.
What the letters mean
A letter after the three digits is the tolerance, which is how far the real value may sit from the marked one. The page reads B, C, D, F, G, H, J, K, M and Z and shows each as a plus and minus range. A code with no letter is shown as not marked, because the tolerance may be printed elsewhere or not at all.
Other markings on the body, such as a voltage rating or a temperature code, are separate from the value code. They are not decoded here. Always check the datasheet for any part that matters to a circuit.
Working on a circuit board
If the same board has surface mount resistors, use the SMD Resistor Code Calculator. For through-hole resistors, read the bands with the Resistor Color Code Calculator, and check currents and voltages with the Ohm's Law Calculator.
Assumptions and limits
- The third digit is a power of ten. The digits 6 and 7 are not used in this code.
- Tolerance letters follow the usual capacitor lettering and are shown as printed ranges.
- Voltage and temperature codes are not decoded.
- Confirm any part against its datasheet before relying on it.
Frequently asked questions
What does a capacitor marked 104 mean?
It means 10 followed by 4 zeros in picofarads, which is 100,000 pF, 100 nF or 0.1 uF. It is one of the most frequently seen ceramic capacitor values.
How do I convert pF to nF and uF?
Divide picofarads by 1,000 for nanofarads, and divide nanofarads by 1,000 for microfarads. So 2,200 pF is 2.2 nF, and 1,000,000 pF is 1 uF.
What does the letter after the code mean?
It is the tolerance. For example J is plus or minus 5 percent, K is 10 percent and M is 20 percent. The page lists every letter it understands.
Why is there an R in a capacitor code?
An R stands for a decimal point in small values. The code 4R7 reads as 4.7 pF, and R47 reads as 0.47 pF.