Capacitor Code Calculator

Decode 3-digit ceramic capacitor codes, convert capacitance values to codes, and calculate series & parallel totals. Includes E12 / E24 standard value reference.

    Common Ceramic Capacitor Codes (E12 / E24)

    Standard 3-digit codes for E12 (±10%) and E24 (±5%) preferred values across common decades.

    Base Value 10 pF 100 pF 1 nF 10 nF 100 nF 1 µF

    How to read: the first two digits are the significant figures, the third digit is the multiplier (number of zeros to add, in picofarads). Example: 104 = 10 + 4 zeros = 100,000 pF = 100 nF = 0.1 µF.

    Formulas

    Capacitor Code (picofarads)

    C = (first two digits) × 10third digit pF

    Unit Conversions

    Parallel Capacitors

    Ctotal = C₁ + C₂ + C₃ + …

    Capacitances simply add together in parallel (like resistors in series).

    Series Capacitors

    1 / Ctotal = 1/C₁ + 1/C₂ + 1/C₃ + …

    The total is always less than the smallest capacitor (like resistors in parallel). For two capacitors: Ctotal = (C₁ × C₂) / (C₁ + C₂).

    FAQ

    What does a 3-digit capacitor code like 104 mean?
    The first two digits are the significant figures and the third is the multiplier (power of ten in picofarads). So 104 = 10 × 10⁴ pF = 100,000 pF = 100 nF = 0.1 µF. Likewise 103 = 10 nF, 102 = 1 nF, and 101 = 100 pF.
    How are capacitors under 10 pF marked?
    Values below 10 pF use an "R" to indicate the decimal point. For example 4R7 = 4.7 pF, 2R2 = 2.2 pF, and 8R2 = 8.2 pF. This calculator handles both 3-digit codes and R-notation.
    What are the E12 and E24 standard value series?
    E12 (±10%) has 12 values per decade: 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82. E24 (±5%) adds intermediate values for 24 per decade: 10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82, 91. These are the preferred values most ceramic capacitors are manufactured in.
    Should I wire filter capacitors in series or parallel?
    For most applications you wire capacitors in parallel to increase total capacitance (they add up). Use series only when you need a specific smaller value, higher voltage rating, or a non-standard value from parts on hand. Remember: series total is always less than the smallest individual capacitor.
    Why doesn't my value convert to a clean 3-digit code?
    Only values that fit the E-series produce exact 3-digit codes. If your value doesn't match (e.g. 150 pF gives "151" exactly, but 145 pF has no exact code), the calculator rounds to the nearest representable code. Always pick the nearest E12/E24 preferred value for production designs.
    How do I read a 3-digit ceramic capacitor code?
    The first two digits are significant figures and the third is the multiplier (power of 10 in picofarads). For example: 104 = 10 × 10,000 = 100,000 pF = 100 nF = 0.1 µF. 22pF is marked as '22' (zero multiplier). 4.7nF is '472' (47 × 100). Any letter suffix like K (±10%) or J (±5%) indicates tolerance.
    What's the difference between pF, nF, and µF?
    They're metric prefixes for the same unit: 1 µF (microfarad) = 1,000 nF (nanofarads) = 1,000,000 pF (picofarads). Small ceramic capacitors are usually labeled in pF. Mid-range values are often shown in nF. Large electrolytic capacitors use µF. A 100 nF decoupling cap is the same as 0.1 µF or 100,000 pF.
    How do series and parallel capacitor connections differ?
    Parallel: capacitances add directly (C_total = C1 + C2). More capacitance, same voltage rating. Series: use reciprocal formula (1/C_total = 1/C1 + 1/C2). Total is less than the smallest cap, but voltage rating increases. This is opposite to resistors — capacitors in series reduce total capacitance just like resistors in parallel reduce total resistance.
    What are E12 and E24 standard values?
    E12 defines 12 values per decade (10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82) for ±10% tolerance. E24 adds intermediate values for ±5%. These preferred number series ensure standard components are available at predictable intervals. Common decoupling caps (100nF, 10nF, 1nF) all fall on E12/E24 values, making them inexpensive and widely stocked.

    How to Use the Capacitor Code Calculator

    1. Enter a 3-digit capacitor code (e.g., 104) to decode it to a capacitance value. The first two digits are significant; the third is the multiplier (number of zeros to add in picofarads).
    2. Or enter a capacitance value in pF, nF, or µF to convert it back to a 3-digit code for identification.
    3. Use the series/parallel calculator to compute total capacitance for multiple capacitors connected together.
    4. Reference the E12/E24 table for standard capacitor values used in circuit design.
    5. Copy the results for use in your schematic, BOM, or circuit simulation.

    Understanding Capacitor Codes and Values

    Ceramic capacitors use a compact 3-digit code system to mark their capacitance value on small components where full markings don't fit. The system works in picofarads (pF): the first two digits are the significant figures, and the third digit is the multiplier — the power of ten. For example, code 104 means 10 × 10⁴ = 100,000 pF = 100 nF = 0.1 µF, one of the most common decoupling capacitor values. Code 22 means 22 × 10⁰ = 22 pF. Code 472 means 47 × 10² = 4,700 pF = 4.7 nF. The letter suffix (K = ±10%, J = ±5%, M = ±20%) indicates tolerance.

    Capacitance unit conversion follows metric prefixes: 1 microfarad (µF) = 1,000 nanofarads (nF) = 1,000,000 picofarads (pF). This three-tier system exists because capacitor values span an enormous range — from fractions of a picofarad in RF circuits to thousands of microfarads in power supply filters. When reading schematics, you'll see values expressed in different units depending on magnitude: pF for small ceramic caps, nF for mid-range, and µF for electrolytic types. Engineers develop an intuitive feel for common conversions like 100 nF = 0.1 µF and 10 nF = 0.01 µF.

    For circuit design, the E-series of preferred numbers defines standard capacitor values, similar to resistor values. E12 (12 values per decade: 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82) covers ±10% tolerance components and is the most common for ceramic capacitors. E24 adds intermediate values for ±5% tolerance. When connecting multiple capacitors, parallel connection adds values directly (C_total = C1 + C2 + ...), while series connection uses the reciprocal formula (1/C_total = 1/C1 + 1/C2 + ...), resulting in a total less than the smallest individual capacitor — the opposite of resistors.

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