Capacitor Code Guide: Markings, Color Codes & Values
Ceramic Capacitor Codes
Small ceramic and film capacitors use a 3-digit code printed on the body:
- Digits 1–2: Significant figures
- Digit 3: Multiplier (number of zeros)
- Letter: Tolerance
Example: 104K = 10 × 10⁴ pF = 100,000 pF = 100 nF = 0.1 μF, ±10%
Common Capacitor Values
| Code | Value (pF) | Value (nF) | Value (μF) |
|---|---|---|---|
| 100 | 10 | 0.01 | 0.00001 |
| 101 | 100 | 0.1 | 0.0001 |
| 102 | 1,000 | 1.0 | 0.001 |
| 103 | 10,000 | 10 | 0.01 |
| 104 | 100,000 | 100 | 0.1 |
| 105 | 1,000,000 | 1,000 | 1.0 |
| 221 | 220 | 0.22 | 0.00022 |
| 222 | 2,200 | 2.2 | 0.0022 |
| 223 | 22,000 | 22 | 0.022 |
| 224 | 220,000 | 220 | 0.22 |
| 334 | 330,000 | 330 | 0.33 |
| 474 | 470,000 | 470 | 0.47 |
| 684 | 680,000 | 680 | 0.68 |
Tolerance Codes
| Letter | Tolerance |
|---|---|
| B | ±0.1 pF |
| C | ±0.25 pF |
| D | ±0.5 pF |
| F | ±1% |
| G | ±2% |
| J | ±5% |
| K | ±10% |
| M | ±20% |
| Z | +80% / −20% |
Voltage Ratings
| Code | Voltage |
|---|---|
| 1E | 25V |
| 1H | 50V |
| 2A | 100V |
| 2D | 200V |
| 2E | 250V |
| 2G | 400V |
| 2J | 630V |
| 3A | 1,000V |
Capacitance Unit Conversions
- 1 μF (microfarad) = 1,000 nF = 1,000,000 pF
- 1 nF (nanofarad) = 0.001 μF = 1,000 pF
- 1 pF (picofarad) = 0.001 nF = 0.000001 μF
Common Mistakes
- Confusing 104 with 10×4: 104 means 10 × 10⁴ = 100,000 pF, NOT 10 × 4 = 40 pF.
- Mixing up nF and μF: 100 nF = 0.1 μF. Don't confuse them — a 100μF cap is 1000× larger than a 100nF cap.
- Ignoring voltage rating: A capacitor rated 25V used in a 50V circuit will fail catastrophically. Always use at least 2× the expected voltage.
Standards Reference
- EIA-198 — Capacitor Marking Codes
- IEC 60062 — Colour Codes for Resistors and Capacitors
- IEC 60384 — Fixed Capacitors
Frequently Asked Questions
What does 104 on a capacitor mean?
104 is a 3-digit code: 10 × 10⁴ pF = 100,000 pF = 100 nF = 0.1 μF. The first two digits (10) are the significant figures and the third digit (4) is the multiplier (4 zeros). This is one of the most common capacitor values in electronics.
How do I read capacitor color codes?
Ceramic disc capacitors sometimes use color bands (similar to resistors). Read bands from top to bottom: digits 1, 2, multiplier, tolerance, voltage. Most modern capacitors use printed numeric codes instead of color bands.
What is the difference between ceramic and electrolytic capacitors?
Ceramic capacitors are small, non-polarized, and used for filtering (pF to low μF range). Electrolytic capacitors are larger, polarized (have + and −), and used for bulk storage (μF to thousands of μF). Never reverse polarity on an electrolytic — it can explode.
Can I replace a capacitor with a higher voltage rating?
Yes, and it's generally recommended. A higher voltage rating provides more safety margin. A 50V capacitor can replace a 25V capacitor in a 12V circuit with no issues. The capacitance value must match, but voltage can be higher (never lower).
What does J, K, M mean on capacitors?
These are tolerance codes: J = ±5%, K = ±10%, M = ±20%. A 104K capacitor is 100 nF ±10%, so the actual value could be 90–110 nF. For precision circuits, use J or tighter tolerance.