The most reliable, bench-tested mnemonic for color code of resistors is "Bad Boys Run Over Your Great Big Violet Garden Wall" (Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White). For the tolerance bands, remember "Good Boys Vote First" (Gold 5%, Brown 1%, Red 2%, None 20%). While modern SMD components rely on printed alphanumeric codes, through-hole axial resistors still dominate prototyping, repair, and high-power applications. Below is the definitive reference for decoding them accurately on the bench.
The Complete IEC 60062 Resistor Color Code Reference
The global standard governing through-hole resistor color bands is IEC 60062. This table maps every valid band color to its digit, multiplier, and tolerance values. Keep this chart at your workstation to eliminate guesswork when sorting mixed bins of 1/4W and 1/2W carbon and metal film resistors.
| Color | Digit (Sig Fig) | Multiplier | Tolerance | Temp Coefficient (6-Band) |
|---|---|---|---|---|
| Black | 0 | ×1 Ω | — | — |
| Brown | 1 | ×10 Ω | ±1% (F) | 100 ppm/°C |
| Red | 2 | ×100 Ω | ±2% (G) | 50 ppm/°C |
| Orange | 3 | ×1 kΩ | — | 15 ppm/°C |
| Yellow | 4 | ×10 kΩ | — | 25 ppm/°C |
| Green | 5 | ×100 kΩ | ±0.5% (D) | — |
| Blue | 6 | ×1 MΩ | ±0.25% (C) | 10 ppm/°C |
| Violet | 7 | ×10 MΩ | ±0.1% (B) | 5 ppm/°C |
| Grey | 8 | ×100 MΩ | ±0.05% (A) | — |
| White | 9 | ×1 GΩ | — | — |
| Gold | — | ×0.1 Ω | ±5% (J) | — |
| Silver | — | ×0.01 Ω | ±10% (K) | — |
Decoding 4, 5, and 6-Band Variants in Practice
Resistors are manufactured with varying band counts depending on their precision and intended application. Misidentifying the band count is the most common reason hobbyists calculate the wrong resistance value.
4-Band Resistors (Standard 5% Carbon/Metal Film)
The 4-band format is the most common for general-purpose circuits. The first two bands represent significant digits, the third is the multiplier, and the fourth is the tolerance.
Example: Yellow (4), Violet (7), Red (×100), Gold (±5%) = 4,700 Ω or 4.7 kΩ ±5%.
5-Band Resistors (Precision 1% Metal Film)
Precision resistors require three significant digits to achieve tight tolerances. The first three bands are digits, the fourth is the multiplier, and the fifth is tolerance.
Example: Brown (1), Black (0), Black (0), Brown (×10), Brown (±1%) = 1,000 Ω or 1.00 kΩ ±1%. Note that the multiplier band uses the exact same color logic as the 4-band system.
6-Band Resistors (High-Reliability & Audio)
The 6-band format adds a temperature coefficient (TCR) band to the 5-band layout, indicating how much the resistance drifts per degree Celsius of temperature change. This is critical in precision analog-to-digital converters and high-fidelity audio crossovers where thermal drift introduces harmonic distortion.
Rows People Get Wrong & Faded Marking Workarounds
Even with the best mnemonic for color code of resistors, physical degradation and poor lighting cause misreads. Here are the specific rows and scenarios that cause failures on the bench, and how to resolve them.
The Most Commonly Confused Colors
- Red vs. Orange (Heat Fade): When a resistor operates near its maximum power rating (e.g., a 1/2W resistor dissipating 0.45W), the phenolic resin body heats up. Over time, this thermal stress causes the red band to oxidize and fade into a dull orange. If a circuit has a history of running hot, suspect a 200 Ω (Red-Black-Brown) resistor has faded to look like 300 Ω (Orange-Black-Brown).
- Gold vs. Yellow (Reflectivity): In dim workshop lighting, a yellow multiplier band (×10 kΩ) can easily be mistaken for a gold tolerance band (±5%), or vice versa. The physical difference is material: Gold bands are painted with metallic, reflective flake paint, while Yellow bands are flat, matte pigment. Tilt the resistor under a bright, cool-white LED to check for metallic sparkle.
- Green vs. Blue (Lighting Shift): Standard warm-white household bulbs (2700K) suppress blue wavelengths, making dark blue bands look nearly black or dark green. Always inspect precision resistors under a 5000K daylight-balanced bench lamp.
Safe Interpretation When Markings are Faded or Burnt
If a resistor has suffered catastrophic thermal runaway, the color bands may be completely charred. Never attempt to guess the value based on the physical size of the component; a 1/4W 10 Ω resistor and a 1/4W 1 MΩ resistor are physically identical.
The Fix: Use a soldering iron to lift one leg of the resistor out of the PCB pad, isolating it from the circuit, then measure it with a digital multimeter (DMM). If the resistor reads open (OL) or is significantly out of spec, discard it and calculate the replacement value from the schematic.
Standard Variants: Through-Hole vs. SMD (EIA-96)
While IEC 60062 governs axial leaded resistors globally, surface-mount device (SMD) resistors use entirely different marking standards due to their microscopic size. If you are transitioning from through-hole prototyping to PCB assembly, you must adapt to the EIA-96 standard and basic 3-digit SMD codes.
Standard 3-Digit and 4-Digit SMD Codes
For 5% and 1% SMD resistors (0603, 0805, 1206 packages), the color code is replaced by printed numerals. The logic mirrors the color code: the first two (or three) digits are significant figures, and the last digit is the multiplier (number of zeros).
| Marking | Format | Calculation | Resistance Value |
|---|---|---|---|
| 472 | 3-Digit (5%) | 47 × 10² | 4.7 kΩ |
| 1001 | 4-Digit (1%) | 100 × 10¹ | 1.00 kΩ |
| 2R2 | R-Notation | R replaces decimal | 2.2 Ω |
The EIA-96 Standard for 0603 1% Resistors
Because 0603 packages are too small to print four digits, the EIA-96 standard uses a three-character code: two numbers followed by a letter. The two numbers represent a specific index value from a lookup table (e.g., '01' = 100, '68' = 499), and the letter represents the multiplier. While this lacks the intuitive mnemonic of the color code, it is the universal standard for modern high-density PCBA manufacturing. Always keep an EIA-96 lookup chart in your SMD workstation, as the index numbers are entirely arbitrary and cannot be calculated on the fly like IEC 60062 color bands.
