Capacitor Code Calculator
Decode a capacitor code like 104 into a capacitance, or turn a value back into its 3-digit code, with a realistic capacitor drawing
Accepts 104, 472, 22, 104K, 4u7, n47, 100n, 1n5
Common capacitor codes
| Code | Picofarads | Value |
|---|---|---|
| 101 | 100 | 100 pF |
| 221 | 220 | 220 pF |
| 471 | 470 | 470 pF |
| 102 | 1000 | 1 nF |
| 222 | 2200 | 2.2 nF |
| 472 | 4700 | 4.7 nF |
| 103 | 10000 | 10 nF |
| 223 | 22000 | 22 nF |
| 473 | 47000 | 47 nF |
| 104 | 100000 | 100 nF |
| 224 | 220000 | 220 nF |
| 474 | 470000 | 470 nF |
| 105 | 1000000 | 1 µF |
| 225 | 2200000 | 2.2 µF |
Tolerance letters
A letter after the code gives the tolerance (e.g. 104K = ±10%).
| Letter | Tolerance |
|---|---|
| B | ±0.1 pF |
| C | ±0.25 pF |
| D | ±0.5% |
| F | ±1% |
| G | ±2% |
| J | ±5% |
| K | ±10% |
| M | ±20% |
| Z | +80% / -20% |
About this tool
The capacitor code calculator turns the short code printed on a ceramic or film capacitor into a capacitance value, and works the other way too: type a value and it shows the matching 3-digit code. It understands plain codes like 104 and 472, codes with a tolerance letter like 104K, and engineering notation like 4u7, n47, or 1n5. A realistic capacitor drawing shows the code on the body, and reference tables list the most common codes and the EIA tolerance letters. It is built for makers, electronics students, and hobbyists who need to read a capacitor without reaching for a datasheet.
How to use
- 1 Pick a mode: decode a code into a value, or encode a value into a code.
- 2 In decode mode, type the code printed on the capacitor, such as 104 or 104K.
- 3 In encode mode, enter a capacitance value and choose its unit (pF, nF, or µF) and a tolerance letter.
- 4 Read the capacitance, tolerance, and value range, and check the realistic capacitor drawing.
How it works
Capacitors are too small to print the full capacitance, so they use a compact code in picofarads. A one or two digit code is read directly as picofarads, so 22 means 22 pF. A three digit code uses the first two digits as significant figures and the third as a power-of-ten multiplier, again in picofarads: 104 is 10 × 10^4 = 100000 pF = 100 nF = 0.1 µF, and 472 is 47 × 10^2 = 4700 pF = 4.7 nF. By EIA convention a third digit of 8 means ×0.01 and 9 means ×0.1, so 229 is 22 × 0.1 = 2.2 pF. A trailing letter gives the tolerance: J is ±5%, K is ±10%, M is ±20%, and Z is +80% / −20%, while B, C, and D give an absolute tolerance in picofarads for very small capacitors. Some parts instead print engineering notation where a letter replaces the decimal point, so 4u7 is 4.7 µF and n47 is 0.47 nF.
Frequently asked questions
What does 104 mean on a capacitor?
It is the EIA code 104, read as 10 × 10^4 picofarads = 100000 pF, which is 100 nF or 0.1 µF. The first two digits are significant figures and the third is the number of zeros (the power-of-ten multiplier in picofarads).
What does the letter after the code mean?
It is the tolerance. Common letters are J for ±5%, K for ±10%, and M for ±20%. So 104K is 100 nF with a ±10% tolerance. For very small capacitors, B, C, and D give an absolute tolerance in picofarads instead.
How do I read codes like 4u7 or n47?
These use a letter as the decimal point. 4u7 means 4.7 µF, n47 means 0.47 nF, p47 means 0.47 pF, and 1n5 means 1.5 nF. This calculator accepts both this notation and the plain 3-digit code.
Why is my code not in the common-code list?
The reference table only lists the most frequently used values. The calculator still decodes or encodes any valid code; just type or enter your value and it will compute the result, even if it is not a standard stock value.
Related tools and uses
For other electronics math, try the resistor color code calculator, the Ohm's law calculator, and the series and parallel calculator to combine multiple capacitors.