Resistor Color Code Decoder
Decode 3, 4, 5, and 6 band resistor color values instantly.
Updated
What is the Resistor Color Code Decoder?
Easily decode or encode the colour bands on through‑hole resistors.
Just select the colours you see – or type a resistance value – and get the exact ohm reading, tolerance, and (for 6‑band parts) the temperature coefficient.
Dual‑mode for complete flexibility:
- Decode – pick 3, 4, 5, or 6 bands; the tool instantly shows the resistance.
- Encode – type any standard value (like
4.7k,1M,0.22Ω) and see exactly which colours should be on the resistor.
No install, no uploads – all calculations happen in your browser.
Supports the EIA‑96 standard colour codes, including gold and silver multipliers and all common tolerance values.
How it works
Every resistor colour band represents a digit, multiplier, tolerance, or temperature coefficient according to the international IEC 60062 standard.
| Colour | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 | – |
| 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% |
How the decoder works
- Band count is determined – you select 3, 4, 5, or 6 bands.
- For decoding, the tool reads the first 2 or 3 bands as digits, the next band as the multiplier, and the final band(s) as tolerance and, if present, temperature coefficient.
- Example: Brown(1), Black(0), Red(×100), Gold(±5%) → 10×100 = 1 000 Ω → 1 kΩ ±5%.
- For encoding, you enter a resistance value (e.g.
4.7k). The tool finds the closest standard digit/multiplier combination and maps it to the exact colour bands, automatically picking the nearest standard tolerance colour. - Real‑time validation ensures only colours that make sense for a given band position are available – for instance, the multiplier band can never be black on a 6‑band resistor if the value is non‑zero.
The tool also handles the 6‑band format, where the extra band indicates the temperature coefficient (ppm/°C), shown as brown (100), red (50), orange (15), yellow (25), blue (10), or violet (5).
All computations are performed purely in your browser using TypeScript – no data leaves your device.
Examples
Decode a 4‑band resistor
Select Brown, Black, Red, Gold to get 1 kΩ ±5%.
Encode a 5‑band value
Enter “4.7k” with ±1% tolerance to see Orange, Violet, Black, Brown, Brown.
Decode a 6‑band resistor
Read a precision resistor with temperature coefficient.
Frequently asked questions
What do the coloured bands on a resistor mean?
What do the coloured bands on a resistor mean?
Each colour represents a number, a multiplier, a tolerance, or (on 6‑band resistors) a temperature coefficient. For example, a 4‑band resistor with Brown‑Black‑Red‑Gold reads as 1 (brown), 0 (black), ×100 (red) = 1 000 Ω (1 kΩ) with a ±5% tolerance.
How do I read a 5‑band resistor?
How do I read a 5‑band resistor?
A 5‑band resistor has three significant digits, a multiplier, and a tolerance band. Example: Yellow‑Violet‑Black‑Orange‑Brown → 470 ×1 000 = 470 kΩ ±1%. Use the decoder’s 5‑band mode, pick the colours from left to right, and it calculates the value instantly.
Can I use this tool for 6‑band resistors?
Can I use this tool for 6‑band resistors?
Yes. The sixth band indicates the temperature coefficient (how much the resistance changes with temperature). Simply select 6‑band mode and choose all six colours. The tool will show the resistance, tolerance, and the temp coefficient in ppm/°C.
Why are some colours not available for certain band positions?
Why are some colours not available for certain band positions?
The resistor colour code standard restricts which colours can appear where. For example, gold and silver are only valid as multipliers or tolerance bands – they never appear as significant digits. The decoder automatically filters the palette so you only see valid choices for each position, preventing impossible colour combinations.
How do I encode a resistance value to colours?
How do I encode a resistance value to colours?
Switch to Encode mode, type a value like 4.7k, 1M, or 4700, and choose the desired band count.
The tool calculates the closest standard digit and multiplier combination, then picks the nearest standard tolerance colour (you can adjust the tolerance dropdown if needed).
The resistor graphic updates in real time to show the exact colour bands.
What does the tolerance colour mean?
What does the tolerance colour mean?
Tolerance tells you how much the actual resistance may deviate from the marked value.
- Gold = ±5%
- Silver = ±10%
- Brown = ±1%
- Red = ±2%
- Green = ±0.5%
- Blue = ±0.25%
- Violet = ±0.1%
- Grey = ±0.05% If no tolerance band is shown (3‑band or absent band), the default is ±20%.
Is my data safe? Does the tool send anything to a server?
Is my data safe? Does the tool send anything to a server?
Absolutely safe. All calculations run entirely in your browser using JavaScript. Nothing is sent over the network, and no information is stored. You can use the tool offline once the page has loaded.
Does the decoder support SMD or surface‑mount resistors?
Does the decoder support SMD or surface‑mount resistors?
No – this tool is designed for traditional through‑hole axial resistors that use colour bands.
SMD resistors use numeric codes (like 103, 4R7) that are not covered here. We may add a separate decoder for those in the future.
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