To read a resistor color code, hold the component so the tolerance band (usually gold or silver) is on the far right, then read the color bands from left to right. The global standard governing these markings is IEC 60062. Unlike wire color codes which vary by region, resistor color codes are universal, though the available values are constrained by EIA E-series manufacturing standards.
The Master Resistor Color Code Chart (IEC 60062)
Use this reference table to decode the bands on any standard through-hole carbon film or metal film resistor. Keep this chart at your bench; it applies to 4-band, 5-band, and 6-band components.
| Color | Digit (Bands 1-3) | Multiplier (Band 3 or 4) | Tolerance (Band 4 or 5) | Temp. Coeff. (Band 6) |
|---|---|---|---|---|
| Black | 0 | ×1 (10⁰) | — | 250 ppm/°C |
| Brown | 1 | ×10 (10¹) | ±1% | 100 ppm/°C |
| Red | 2 | ×100 (10²) | ±2% | 50 ppm/°C |
| Orange | 3 | ×1k (10³) | — | 15 ppm/°C |
| Yellow | 4 | ×10k (10⁴) | — | 25 ppm/°C |
| Green | 5 | ×100k (10⁵) | ±0.5% | — |
| Blue | 6 | ×1M (10⁶) | ±0.25% | 10 ppm/°C |
| Violet | 7 | ×10M (10⁷) | ±0.1% | 5 ppm/°C |
| Grey | 8 | — | ±0.05% | — |
| White | 9 | — | — | — |
| Gold | — | ÷10 (10⁻¹) | ±5% | — |
| Silver | — | ÷100 (10⁻²) | ±10% | — |
Decoding 4-Band, 5-Band, and 6-Band Resistors in Practice
The number of bands dictates the precision of the resistor. Here is how to apply the table above based on the physical component in your hand:
- 4-Band (Standard 5% or 10%): Band 1 (Tens), Band 2 (Ones), Band 3 (Multiplier), Band 4 (Tolerance). Example: Yellow-Violet-Red-Gold = 47 × 100 = 4,700Ω (4.7kΩ) ±5%.
- 5-Band (Precision 1% or better): Band 1 (Hundreds), Band 2 (Tens), Band 3 (Ones), Band 4 (Multiplier), Band 5 (Tolerance). Example: Brown-Black-Black-Red-Brown = 100 × 10 = 1,000Ω (1kΩ) ±1%.
- 6-Band (High-Reliability): Same as 5-band, but adds Band 6 for Temperature Coefficient (ppm/°C), indicating how much the resistance drifts as the component heats up under load.
For a complete breakdown of how manufacturers calculate these specific value steps, refer to the EIA standard resistor values guide on All About Circuits.
The "Rows People Get Wrong" (Common Misreads)
Even experienced technicians misread bands under harsh fluorescent bench lighting or when dealing with cheap, poorly painted carbon film resistors. Watch out for these specific traps:
1. Red (2) vs. Orange (3)
A faded red band on a 20-year-old PCB looks almost identical to orange. If you are trying to distinguish between a 2.2kΩ (Red-Red-Red) and a 3.3kΩ (Orange-Orange-Red), rely on the E24 series logic. If the third band is red (×100), the first two bands must form a valid E24 number. Both 22 and 33 are valid, so you must verify with a multimeter if the lighting is poor.
2. Gold as a Multiplier vs. Gold as Tolerance
Gold is never a significant digit. If gold appears as the 3rd band on a 4-band resistor, it is a multiplier (÷10). For example, a 2.2Ω resistor is coded Red-Red-Gold-Gold (22 ÷ 10 = 2.2Ω, ±5%). Beginners often misread this as 22Ω because they assume gold is always the tolerance band. Rule of thumb: The tolerance band is physically spaced slightly further apart from the other bands.
3. Black Multiplier (×1) vs. Black Digit (0)
Beginners often assume a black multiplier means "zero ohms." Black as a multiplier means 10⁰, which equals 1. A resistor coded Brown-Black-Black-Gold is 10 × 1 = 10Ω, not 100Ω and not 0Ω. (Note: A single black band in the center of a component is a zero-ohm jumper link, not a standard resistor).
Faded, Burnt, or Missing Bands: The Troubleshooting Decision Path
When visual inspection fails, you must transition to electrical measurement. Never guess a burnt resistor's value based on surrounding components; a failed resistor may have drifted drastically before burning out. Use this decision tree to determine your next step.
| Symptom / Condition | Required Action | Concrete Tool / Default Part Pick |
|---|---|---|
| Charred or blackened body | Desolder both legs. Measure across the component. If it reads OL (Open Loop), it has failed open. Replace with a higher wattage rating. | Replace with Vishay PR02 2W metal film (flameproof) of the calculated circuit value. |
| Faded or unreadable bands | Measure out-of-circuit. If reading is within ±5% of a standard E24 value, lock in that value. | Use a Fluke 117 True-RMS DMM on the Ohms (Ω) setting. |
| In-circuit reads significantly lower than expected | You are measuring parallel semiconductor paths. Desolder or lift one leg of the resistor from the pad and measure again. | Lift leg using a Hakko FR-301 desoldering station or standard solder wick. |
| Resistor measures shorted (near 0Ω) | Extremely rare for film resistors unless subjected to massive overvoltage. Check for a solder bridge on the PCB pads before condemning the part. | Inspect under a 10x magnification loupe or microscope. |
Standard Variants: E-Series, MIL-Spec, and Wire Code Confusion
While the IEC 60062 color code is universal, the values you encounter are governed by manufacturing standards, and beginners frequently confuse resistor codes with electrical wiring codes.
EIA E-Series (Why you can't buy a 300Ω 5% resistor)
Resistors are manufactured in logarithmic steps known as E-series. A standard 5% resistor uses the E24 series (24 values per decade). The base values are 1.0, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0, 2.2, 2.4, 2.7, 3.0, 3.3, 3.6, 3.9, 4.3, 4.7, 5.1, 5.6, 6.2, 6.8, 7.5, 8.2, and 9.1. Therefore, a 5% 300Ω resistor does not exist; you must use 330Ω or 270Ω. If you see a 300Ω resistor, it will be a 1% tolerance (E96 series) component, coded Orange-Black-Black-Black-Brown on a 5-band layout.
MIL-PRF-22684 and Military Variants
Military-specification resistors (often found in surplus aviation or marine radios) may use a 5-band system where the 5th band indicates reliability/failure rate rather than standard tolerance. For example, a 5th band of Yellow might indicate a failure rate of 0.001% per 1,000 hours. Always cross-reference military boards with the specific DigiKey military resistor calculators if standard IEC decoding yields impossible values.
The Wire Color Code Trap
Do not apply NEC or IEC wire color standards to resistors. In US NEC wiring, Green means "Earth Ground." In IEC 60062 resistor codes, Green means the digit "5" or a ±0.5% tolerance. Similarly, White is a neutral wire in AC mains, but it means the digit "9" on a resistor. Always separate your mains wiring knowledge from your PCB component knowledge to avoid catastrophic misidentifications.
