Capacitor Code Decoder
Decode 3-digit capacitor codes (104, 223 etc.) into capacitance value. Convert between pF, nF, μF, mF.
Key Formulas
Code XY Z = XY × 10Z pF
Example: 104 = 10×104 = 100,000 pF = 100 nF
Frequently Asked Questions
What does the Capacitor Code Decoder calculate?
This tool decodes standard 3-digit ceramic and film capacitor markings (e.g., “104”, “222”) into their actual capacitance value in picofarads (pF), then automatically converts and displays the result in nanofarads (nF), microfarads (µF), and millifarads (mF). It also interprets common tolerance letters (J, K, M, Z) to show the allowable deviation from the nominal value.
Why do some capacitors use 3-digit codes instead of labeled values?
Space constraints on small surface-mount (SMD) and leaded ceramic/film capacitors make full numeric labeling impractical. The 3-digit code is an industry-standard shorthand: the first two digits are significant figures, and the third is the multiplier (power of 10) applied to yield capacitance in pF — enabling compact, unambiguous identification.
What does each digit in a code like “104” represent?
In “104”: “10” are the first two significant digits, and “4” is the exponent of 10. So it means 10 × 10⁴ pF = 100,000 pF = 100 nF = 0.1 µF. Similarly, “473” = 47 × 10³ pF = 47,000 pF = 47 nF.
What tolerance letters does this tool support, and what do they mean?
The tool supports common tolerance codes: J = ±5%, K = ±10%, M = ±20%, and Z = +80% / −20% (typically for electrolytics). These indicate the maximum allowable deviation from the decoded nominal capacitance — critical for timing, filtering, and stability-sensitive circuits.
Can this tool decode codes with letters (e.g., “47J”, “2n2”) or only numeric ones?
No — this tool is designed specifically for standard 3-digit codes (e.g., “104”, “223”). Codes containing letters like “47J” (EIA-198) or alphanumeric formats like “2n2” (2.2 nF) require a different decoding logic and are not supported. For those, refer to the EIA-198 standard or use a multi-format capacitor calculator.
What’s the typical capacitance range covered by 3-digit codes?
Standard 3-digit codes cover ~1 pF to 99,999,999 pF (i.e., 10⁻¹² F to ~10 mF), though most common values fall between 10 pF and 100 µF. Codes like “010” (1 × 10⁰ = 1 pF) or “999” (99 × 10⁹ = 99 nF) are rare but valid; extremely high values (e.g., >100 µF) usually appear as alphanumeric or direct-label formats.
Why does my input return “Invalid code” even when I enter three digits?
The tool validates inputs strictly: all three characters must be digits (0–9), and the code must be exactly 3 characters long. Leading zeros (e.g., “010”) are accepted, but non-numeric entries (e.g., spaces, letters, or fewer/more than three digits) will trigger an error. Double-check for accidental typos or hidden whitespace.
How does this relate to capacitor selection in RC timing or filter design?
Accurate decoding ensures correct time constants (τ = R × C) and cutoff frequencies (fc = 1/(2πRC)). Using an undecoded or misinterpreted value (e.g., reading “104” as 104 pF instead of 100 nF) can cause orders-of-magnitude errors in circuit behavior — making this tool essential for prototyping, debugging, and BOM verification.
Does this tool handle voltage ratings or temperature coefficients?
No — voltage rating (e.g., “50V”), temperature coefficient (e.g., “X7R”, “NPO”), and package size are separate markings not encoded in the 3-digit value. This tool only decodes capacitance and tolerance. Always cross-reference the full part marking and datasheet for full electrical and thermal specifications.
Can I use this for electrolytic or tantalum capacitors?
Most aluminum electrolytics and tantalums use direct labeling (e.g., “10µF 25V”) rather than 3-digit codes. However, some smaller tantalum SMD parts *do* use 3-digit codes — in those cases, the decoder applies, but note that tolerance codes like “Z” may indicate asymmetric tolerances. Always verify with the manufacturer’s datasheet.