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
- 1 nF = 1,000 pF
- 1 µF = 1,000 nF = 1,000,000 pF
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.