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Capacitor Code Calculator (3-digit code, letter markings)

value (pF) = first digits × 10^multiplier pF, nF, µF, V

Standard EIA / IEC 60062 capacitor markings. The 3-digit code is standard for ceramic disc, MLCC, and film caps; the last digit is the multiplier (power of 10), giving the value in picofarads. Some caps use dot codes, direct µF markings (e.g. "4µ7"), or manufacturer-specific schemes not covered here. Always verify large or high-voltage caps against the datasheet.

Why capacitor markings are confusing

Resistors have neat color bands with a well-known mnemonic. Capacitors have a mess: 3-digit numeric codes on ceramics, letter codes for tolerance and voltage, dielectric-type codes like X7R and C0G that mean different things, and direct-value markings like “4µ7” that hide the decimal point inside the letter. This calculator handles all of them.

How to use this calculator

Three modes cover every capacitor marking question:

  • Code → Value — enter the numeric code and optionally the tolerance letter and voltage code. Get the capacitance in pF, nF, and µF side by side, plus the tolerance range and voltage rating.
  • Value → Code — enter the capacitance value in any unit, get the standard 3-digit or 4-digit EIA code. The calculator warns you if the target value doesn’t exactly match a standard code.
  • Marking lookup — paste any marking you don’t recognize. Handles combined codes (104K), dielectric types (X7R, C0G, Y5V), voltage codes (1H = 50V), and direct notations (4µ7, 4n7).

The 3-digit ceramic capacitor code

The most common code on ceramic disc and MLCC capacitors is a 3-digit number:

  • First two digits = significant digits
  • Third digit = multiplier (power of 10)
  • Result is in picofarads (pF)

Example: code 104 = 10 × 10⁴ pF = 100,000 pF = 100 nF = 0.1 µF. That’s the classic decoupling capacitor you see on every digital board.

Common codes worth memorizing:

  • 101 = 100 pF
  • 102 = 1 nF (1000 pF)
  • 103 = 10 nF
  • 104 = 100 nF = 0.1 µF (the universal decoupling cap)
  • 105 = 1 µF
  • 106 = 10 µF
  • 473 = 47 nF
  • 474 = 470 nF

4-digit codes for precision caps

Precision capacitors (1% or 2% tolerance) use a 4-digit code instead: first three digits are significant, fourth is the multiplier. Example: 1002 = 100 × 10² pF = 10 nF. Same underlying logic, one more significant digit.

Tolerance letters

A letter after the numeric code indicates tolerance. The most common:

  • J = ±5% (precision, common on Class 1 dielectrics)
  • K = ±10% (standard for general-purpose)
  • M = ±20% (Y5V, Z5U, and bulk electrolytics)
  • F = ±1%, G = ±2% (rare on ceramics, common on film caps)
  • B/C/D = ±0.1 / ±0.25 / ±0.5 pF (absolute tolerance for small caps under 10 pF)
  • Z = +80% / −20% (aluminum electrolytics, Y5V ceramics — wildly imprecise but cheap)

Voltage codes

Some caps are marked with a two-character voltage code instead of a plain voltage. The format is a digit + letter:

  • 1A = 10 V · 1C = 16 V · 1E = 25 V · 1H = 50 V
  • 2A = 100 V · 2D = 200 V · 2E = 250 V · 2G = 400 V · 2H = 500 V
  • 0J = 6.3 V (common on tantalum caps)

These codes come from EIA-198 and are used mostly on aluminum electrolytics, tantalums, and some ceramics. A cap marked “104K 1H” is 100 nF ±10% 50V.

Dielectric type codes (Class 2 ceramics)

Modern MLCC ceramics are marked with a 3-character code describing their temperature behavior:

  • C0G / NP0 — Class 1, ±30 ppm/°C. Precision, low loss, temperature stable. Use for filters, oscillators, precision timing. Small values only (usually ≤ 10 nF).
  • X7R — Class 2, ±15% capacitance over −55 to +125°C. Workhorse for decoupling and bypass. General purpose.
  • X5R — Class 2, ±15% over −55 to +85°C. Same use as X7R but narrower temperature range.
  • X8R — Class 2, ±15% over −55 to +150°C. Automotive and high-temperature.
  • Y5V — Class 2, +22% / −82% over −30 to +85°C. High-density bulk cap. Terrible for precision — do not use for filters or timing.
  • Z5U — Class 2, +22% / −56% over +10 to +85°C. Similar to Y5V.

The stability difference matters: swap a Y5V for an X7R in a precision filter and the filter cutoff frequency will shift dramatically with temperature. This is one of the most common causes of “why does my circuit only work at room temperature” problems.

Direct µF notation

Larger film and electrolytic caps often show the value directly with a decimal-substitute letter:

  • 4µ7 or 4u7 = 4.7 µF
  • 4n7 = 4.7 nF = 4700 pF
  • 4p7 = 4.7 pF

The letter (p, n, µ/u/m) plays the role of the decimal point and the unit. This convention avoids the ambiguity of “.47” (is that a decimal, or “47” with a dot?) especially on small components where a period might be lost in printing.

What this calculator doesn’t cover

  • Older color-band capacitors — rare today, but some vintage caps use dot codes similar to resistors
  • Manufacturer-specific date codes — a 4-digit code on the cap body may be a date code (YYWW) rather than a value code; look for a marked cap datasheet
  • Japanese JIS codes — some older Japanese caps used JIS marking conventions with different tolerance letters
  • ESR / ESL ratings — for high-current or high-frequency use, the equivalent series resistance matters as much as the capacitance value; always check the datasheet

When in doubt, check the manufacturer’s datasheet. The physical cap markings tell you the value and voltage, but the datasheet tells you everything else that matters for real applications.

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