Capacitor Value Calculator
Decode ceramic capacitor codes or convert between pF, nF, and µF.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Capacitor Value Calculator
Ceramic and film capacitors are marked with a 3-digit code instead of a printed value. This calculator decodes those markings and converts between pF, nF, and µF in either direction.
- Choose decode or encode. Decode reads a code from a capacitor body and tells you the value. Encode takes a value and gives you the 3-digit code.
- For decoding: Enter the 3-digit code printed on the capacitor (e.g., 104). The first two digits are significant figures, the third is the power-of-ten multiplier.
- For encoding: Enter the capacitance value and select the unit (pF, nF, or µF). The calculator outputs the standard 3-digit code.
- Read the results. The breakdown shows the value in all three common units (pF, nF, µF) so you can use whichever is most convenient.
About Capacitor Codes
The 3-digit capacitor code works similarly to a resistor color code. For a code like "104": the first two digits (10) are the significant figures, and the third digit (4) is the multiplier — 10 to the power of 4, which is 10,000. So 10 × 10,000 = 100,000 pF = 100 nF = 0.1 µF.
The base unit is always picofarads (pF). Common codes you will encounter: 100 = 10 pF, 101 = 100 pF, 102 = 1 nF, 103 = 10 nF, 104 = 100 nF (0.1 µF), 105 = 1 µF. Electrolytic capacitors usually have their value printed directly in µF.
Frequently Asked Questions
What does the capacitor code 104 mean?
The code 104 on a ceramic capacitor means 10 × 10⁴ picofarads = 100,000 pF = 100 nF = 0.1 µF. The first two digits (10) are significant figures and the third digit (4) is the power-of-ten multiplier. This is one of the most common capacitor values in electronics, used in decoupling, filtering, and timing circuits.
What is the difference between pF, nF, and µF?
These are all units of capacitance, just different scales. 1 µF (microfarad) = 1000 nF (nanofarad) = 1,000,000 pF (picofarad). Small ceramic capacitors used in RF and timing circuits are typically in the pF to nF range. Electrolytic capacitors for power supply filtering are typically 1 µF to 10,000 µF. Supercapacitors can be 1 F or more.
How do I read a capacitor with letters in the code?
Letters after a numeric code usually indicate the tolerance: J = ±5%, K = ±10%, M = ±20%, Z = -20%/+80% (for electrolytics). A letter before the number (like 'n' or 'µ') is part of the value notation, where the letter replaces the decimal point: 4n7 = 4.7 nF, 100p = 100 pF. This calculator handles the standard 3-digit numeric code format.
Why do some capacitors have no number code?
Small capacitors (under 10 pF) and some surface-mount components are too small to mark clearly and may have no markings. Large electrolytic capacitors typically print their value directly (e.g., "100µF 25V"). Tantalum capacitors often use a 3-digit code plus a letter for voltage rating. If a capacitor is unmarked, you need to measure it with a capacitance meter or look up the circuit schematic.