How to Read Resistor Colour Codes: 4-Band, 5-Band, and 6-Band Guide
Resistor colour codes encode the resistance value directly on the component body. Learn to decode 4-band, 5-band, and 6-band resistors, understand tolerance and temperature coefficient bands, and remember the colour sequence with a mnemonic.
Why Colour Codes?
Resistors are tiny. Printing a resistance value in numbers requires a legible font, which is impossible on small components. The colour band system encodes the value visually — even under soldering conditions, the colours are readable.
The Colour-Value Mapping
Each colour corresponds to a digit (0–9), a multiplier, and a tolerance:
| Colour | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 (10⁰) | — |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1,000 | — |
| Yellow | 4 | ×10,000 | — |
| Green | 5 | ×100,000 | ±0.5% |
| Blue | 6 | ×1,000,000 | ±0.25% |
| Violet | 7 | ×10,000,000 | ±0.1% |
| Grey | 8 | ×100,000,000 | ±0.05% |
| White | 9 | ×1,000,000,000 | — |
| Gold | — | ×0.1 | ±5% |
| Silver | — | ×0.01 | ±10% |
| None | — | — | ±20% |
Mnemonic: "Better Be Right Or Your Great Big Venture Goes Wrong" — Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White.
4-Band Resistors
The most common format:
Band 1: 1st significant digit
Band 2: 2nd significant digit
Band 3: Multiplier
Band 4: Tolerance
Example: Red, Violet, Brown, Gold
- Red = 2
- Violet = 7
- Brown = ×10
- Gold = ±5%
Value: 27 × 10 = 270Ω ±5%
5-Band Resistors
Used for precision (1% tolerance and better) resistors:
Band 1: 1st significant digit
Band 2: 2nd significant digit
Band 3: 3rd significant digit
Band 4: Multiplier
Band 5: Tolerance
Example: Red, Red, Black, Brown, Brown
- Red = 2
- Red = 2
- Black = 0
- Brown = ×10
- Brown = ±1%
Value: 220 × 10 = 2,200Ω (2.2kΩ) ±1%
6-Band Resistors
Adds a sixth band for temperature coefficient (tempco):
Band 6: Temperature coefficient (ppm/°C)
| Colour | Tempco (ppm/°C) |
|---|---|
| Brown | 100 |
| Red | 50 |
| Orange | 15 |
| Yellow | 25 |
| Blue | 10 |
| Violet | 5 |
Tempco indicates how much the resistance changes per degree Celsius change. Brown (100ppm/°C) means a 10kΩ resistor changes by 1Ω per °C. Violet (5ppm/°C) is far more stable and used in precision measurement circuits.
Which End to Read From?
The tolerance band (gold, silver, or a tighter-tolerance colour) is at one end. The wider spacing between the tolerance band and its neighbour also helps identify orientation.
For a 4-band resistor: the gold or silver band is always the tolerance (last band), so start reading from the opposite end.
E-series Standard Values
Resistors are manufactured in the E-series standard values: E12, E24, E48, E96, E192. E24 (24 values per decade) is the most common for general use: 10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82, 91 (×10ⁿ).
You will not find a 14Ω resistor in a general shop — the nearest E24 values are 13Ω and 15Ω. When designing circuits, calculate the ideal value first, then select the nearest available E-series value and verify the result is within tolerance for your application.