Resistor Color Code Calculator | 4-Band & 5-Band Decoder
Decode resistor color bands to find resistance value and tolerance. Supports 4-band and 5-band resistors. Also encode a resistance value back to color bands.
How to Use
- Select '4-Band' or '5-Band' mode depending on your resistor type.
- In Decode mode: select the color of each band from left to right. The resistance value and tolerance are displayed instantly.
- In Encode mode: enter the desired resistance value in ohms. The tool will show the matching color bands.
- For 4-band resistors: Band 1 & 2 are digits, Band 3 is multiplier, Band 4 is tolerance.
- For 5-band resistors: Band 1, 2 & 3 are digits, Band 4 is multiplier, Band 5 is tolerance.
- Gold and silver are only used as multiplier or tolerance bands, never as digit bands.
About Resistor Color Codes
The Color Code System
Resistor color codes are standardized under IEC 60062. Each color represents a digit (0–9), a multiplier power of 10, or a tolerance percentage. The system was introduced in the 1920s when resistor bodies were too small for printed text. Reading from left to right, the bands encode the resistance value and its precision (tolerance).
4-Band vs 5-Band Resistors
Standard resistors use 4 color bands: two significant digits, a multiplier, and a tolerance band (gold=±5%, silver=±10%). Precision resistors use 5 bands: three significant digits, a multiplier, and a tolerance (brown=±1%, red=±2%, green=±0.5%). 5-band resistors are used where tight tolerance is required, such as in precision measurement circuits.
Memory Aid for Color Order
A common mnemonic for the color digit sequence (Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Grey=8, White=9) is: 'B.B. ROY of Great Britain has a Very Good Wife.' The first letters match B=0, B=1, R=2, O=3, Y=4, G=5, B=6, V=7, G=8, W=9.
Reading the Multiplier Band
The multiplier band tells you the power of 10 to multiply the digit value by. For example, Red (×100) on a 4-band resistor with digits 4 and 7 gives 47 × 100 = 4,700Ω = 4.7kΩ. Gold (×0.1) and Silver (×0.01) multipliers are used for values below 10Ω. Always hold the resistor so the tolerance band (gold/silver) is on the right.
Key Features
- Supports both 4-band and 5-band resistor decoding
- Bidirectional: decode colors to value or encode value to colors
- Visual color band display with accurate color representation
- Shows tolerance range (min/max resistance values)
- Handles standard E12, E24, E96 series values
Common Applications
- Identifying resistor values without a multimeter
- Selecting correct resistors for circuit assembly
- Quality checking component bins and storage
- Teaching electronics fundamentals in schools and workshops
- PCB assembly and repair work