Translate bands into resistance values instantly
Supports 4-band, 5-band, and 6-band resistor colour codes. See the nominal resistance, tolerance, and temperature coefficient (for 6-band) as you pick colours, plus the closest preferred E-series values. The reverse lookup mode suggests colour bands from a target resistance.
- 1Bidirectional colour ↔ value solver with live updates
- 2Shareable URLs and local favourites for frequent combos
- 3Nearest E24 / E96 picks for procurement-friendly values
- 4Touch-friendly swatch UI tuned for phones and tablets
How to use (3 steps)
- Choose “Colours → Value” or “Value → Colours” from the tabs above.
- Select the band count and each band colour, or enter a target resistance, tolerance, and tempco.
- Check the result, then copy the URL or save as a favourite if you want to reuse the same setup.
All calculations run only in your browser and your input values are not sent to any server.
This result shows the nominal resistance and tolerance range derived from the selected band colours.
This result is an example of a colour code close to your target value and is meant as a guide when choosing components.
Reference table
Not every colour is valid for every band. Temperature coefficients apply to precision 6-band resistors.
| Colour | Digit | Multiplier | Tolerance | Temp. coefficient |
|---|---|---|---|---|
| Black | 0 | ×100 | — | 250 ppm/K |
| Brown | 1 | ×101 | ±1% | 100 ppm/K |
| Red | 2 | ×102 | ±2% | 50 ppm/K |
| Orange | 3 | ×103 | ±3% | 15 ppm/K |
| Yellow | 4 | ×104 | ±4% | 25 ppm/K |
| Green | 5 | ×105 | ±0.5% | 20 ppm/K |
| Blue | 6 | ×106 | ±0.25% | 10 ppm/K |
| Violet | 7 | ×107 | ±0.1% | 5 ppm/K |
| Gray | 8 | ×108 | ±0.05% | 1 ppm/K |
| White | 9 | ×109 | — | 0.5 ppm/K |
| Gold | — | ×10-1 | ±5% | — |
| Silver | — | ×10-2 | ±10% | — |
| None | — | — | ±20% | — |
FAQ
Which band count should I choose?
Standard carbon film resistors are 4-band, metal film parts typically use 5 bands, and precision parts with thermal tracking add a 6th temperature coefficient band.
Can I derive colours from a value?
Yes. Use the “Value → Colours” tab, enter your value and tolerance, then submit to get a suggested colour code.
What are the E-series suggestions?
They show the nearest IEC preferred values (E24/E96) so you can match against commonly stocked resistors.
What should I enter first?
Start with the minimum required inputs shown above the calculate button, then keep optional settings at their defaults for a first pass. After getting a baseline, change one parameter at a time so you can explain which assumption moved the output.
How precise are the results?
The calculator keeps internal precision and rounds only for display. Small differences can still appear if another tool uses different constants, period conventions, or rounding rules. Align assumptions before comparing final values.
How it’s calculated
- 4/5‑band codes use significant digits, a multiplier band, and a tolerance band (6‑band adds a tempco band).
- Nominal resistance = significant digits × multiplier; tolerance is applied as a ±% range.
- The shareable URL keeps your band colours and mode so you can reopen the same configuration later.
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