Color coded capacitors use a painted band or dot system—typically 3 to 5 bands—where the first two colors represent significant digits, the third is a multiplier in picofarads (pF), and subsequent bands indicate tolerance and voltage rating. While modern surface-mount and electrolytic capacitors rely on printed alphanumeric text, vintage tubular axials, ceramic discs, and mica 'postage stamp' capacitors still appear frequently in repair benches, tube amplifier restorations, and legacy industrial equipment.
The Master EIA/IEC Color Code Reference Table
The following table consolidates the standard Electronic Industries Alliance (EIA) RS-402 and IEC 60062 color mappings for tubular and ceramic capacitors. Read the bands from left to right (or top to bottom for axial leads). The base unit for the multiplier is always picofarads (pF).
| Color | Digit (Bands 1 & 2) | Multiplier (Band 3) | Tolerance (Band 4) | Voltage Rating (Band 5) |
|---|---|---|---|---|
| Black | 0 | x1 | ±20% | 15V |
| Brown | 1 | x10 | ±1 pF (or ±1%) | 20V |
| Red | 2 | x100 | ±2 pF (or ±2%) | 2.5V |
| Orange | 3 | x1,000 | — | 3V |
| Yellow | 4 | x10,000 | — | 4V |
| Green | 5 | x100,000 | ±0.5 pF (or ±5%) | 5V |
| Blue | 6 | — | ±1% (Film/Ceramic) | 6.3V |
| Violet | 7 | — | — | — |
| Gray | 8 | — | ±0.25 pF | — |
| White | 9 | x0.1 | ±10% | 10V |
How to read this in practice: A tubular capacitor with Brown, Black, Red, White bands translates to 1 (Brown), 0 (Black), multiplied by 100 (Red) = 1,000 pF (or 1 nF). The White band indicates a ±10% tolerance. If a fifth band is present (e.g., Blue), it dictates the maximum DC working voltage (6.3V).
The 'Rows People Get Wrong' Field Guide
Capacitor color codes share the same base digit mapping as resistor color codes, but the context of the outer bands is entirely different. Here is where bench mistakes happen:
- The Multiplier Trap (Assuming Ohms): The most common error is reading the multiplier as a base unit. A 'Red-Red-Orange' capacitor is not 22,000 of some base unit; it is 22,000 picofarads (22 nF or 0.022 µF). Always anchor your mental math to pF first, then convert to nF or µF.
- Gold and Silver Anomalies: In resistors, Gold means ±5% tolerance and Silver means ±10%. In older EIA tubular capacitors, Gold and Silver are rarely used for tolerance. Instead, a Gold band often indicates a specific high-voltage rating (e.g., 500V DC for vintage wax/paper caps) or denotes a temperature coefficient class. If you see Gold on a vintage capacitor, do not assume 5% tolerance; check the voltage rating tables for that specific manufacturer.
- Tolerance on Low-Value Caps: Notice the Brown and Green rows in the tolerance column specify '±1 pF' and '±0.5 pF' rather than percentages. This applies only to capacitors valued under 10 pF. A 4.7 pF capacitor with a Brown tolerance band is 4.7 pF ±1 pF (meaning it could range from 3.7 to 5.7 pF), not ±1%.
- Temperature Coefficient vs. Voltage: On 6-band ceramic disc capacitors (often MIL-SPEC), the 6th band does not indicate voltage; it indicates the temperature coefficient (e.g., Black for 0±30 ppm/°C, Brown for -30±30 ppm/°C). Confusing the tempco band for a voltage rating can lead to catastrophic failure in high-temperature environments.
Regional Standards, Vintage Parts, and Faded Markings
While the EIA standard dominated North American manufacturing, global and military variants introduce slight deviations you must account for when sourcing replacements or repairing imported gear.
| Standard Body | Region / Application | Key Deviations from Base EIA |
|---|---|---|
| EIA (RS-402) | US Commercial / Consumer | Standard 3-to-5 band system. Tolerance and voltage bands are strictly color-coded as in the master table. |
| IEC 60062 | Europe / Global | Largely aligns with EIA for digits/multipliers, but heavily favors alphanumeric printing over color bands on modern film caps. When bands are used, the voltage color mapping sometimes shifts (e.g., Gray for 16V in specific German DIN variants). |
| MIL-SPEC (MIL-C-11015) | US Defense / Aerospace | Uses a 5- or 6-band system where the final band is strictly a temperature coefficient (e.g., White = ±30 ppm/°C). Voltage is often printed as a separate text string rather than a color band. |
| JIS (Japan) | Asian Vintage Audio | Older Japanese ceramic caps sometimes used a 3-dot system where the third dot was exclusively tolerance, omitting the voltage band entirely (assume 50V standard for signal paths). |
Vintage 'postage stamp' mica capacitors and tubular wax caps from the 1950s-70s frequently suffer from oxidized, flaking, or completely faded paint dots. Never guess the voltage rating on a faded tube amplifier coupling capacitor. If the voltage dot is missing, assume a maximum of 50V for signal paths, but derate by 50% for safety. If the capacitor is in a high-voltage B+ rail, it must be replaced with a modern rated equivalent (e.g., 630V or 1kV film/ceramic) regardless of the faded color code.
Safe Interpretation and Bench Testing Protocol:
When color bands are illegible, do not rely on visual guessing for timing circuits or RF filters where exact capacitance dictates frequency response. Use a dedicated LCR meter (such as the DER EE DE-5000 or Keysight U1733C) rather than a standard multimeter's capacitance function.
- Discharge and Isolate: Safely discharge the capacitor and lift one leg from the circuit to prevent parallel impedance from skewing the reading.
- Select Test Frequency: Set the LCR meter to 1 kHz for standard ceramic/film caps. For electrolytic or high-value vintage paper caps, drop the test frequency to 100 Hz or 120 Hz to get an accurate bulk capacitance reading.
- Measure Dissipation Factor (DF): If the color code is gone, the dielectric health is also suspect. A DF (or ESR) reading significantly higher than the manufacturer's original spec for that physical size indicates the dielectric has dried out or degraded, meaning the part should be binned regardless of its measured capacitance value.
By anchoring your readings to the pF multiplier and verifying the specific standard (EIA vs. MIL) printed on the component's datasheet or chassis schematic, you can accurately decode nearly any color coded capacitor on the bench.
