# Resistor Calculator

> Decode the colour bands on a 4-, 5- or 6-band resistor into its resistance, tolerance, minimum and maximum value and temperature coefficient.

Category: Science & engineering · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/resistor-calculator

Read the bands from the end opposite the gold or silver tolerance band. The first two or three bands are digits, the next is the multiplier, then the tolerance.

Also called: Resistor colour code calculator, Resistor color code decoder.

## Inputs
- Number of bands (options: 4 bands, 5 bands, 6 bands; default 4)
- Band 1 (first digit) (options: Black (0), Brown (1), Red (2), Orange (3), Yellow (4), Green (5), Blue (6), Violet (7), Grey (8), White (9); default brown)
- Band 2 (second digit) (options: Black (0), Brown (1), Red (2), Orange (3), Yellow (4), Green (5), Blue (6), Violet (7), Grey (8), White (9); default green)
- Band 3 (third digit, 5 and 6 bands only) (options: Black (0), Brown (1), Red (2), Orange (3), Yellow (4), Green (5), Blue (6), Violet (7), Grey (8), White (9); default black)
- Multiplier band (options: Black (×1), Brown (×10), Red (×100), Orange (×1k), Yellow (×10k), Green (×100k), Blue (×1M), Violet (×10M), Grey (×100M), White (×1G), Gold (×0.1), Silver (×0.01); default red)
- Tolerance band (options: Brown (±1%), Red (±2%), Orange (±0.05%), Yellow (±0.02%), Green (±0.5%), Blue (±0.25%), Violet (±0.1%), Grey (±0.05%), Gold (±5%), Silver (±10%), No band (±20%); default gold)
- Temperature coefficient band (options: Brown (100 ppm/K), Red (50 ppm/K), Orange (15 ppm/K), Yellow (25 ppm/K); default brown)

## Results
- Resistance
- In ohms
- Tolerance
- Minimum value
- Maximum value
- Temperature coefficient

## Formula

```
Resistance = (digits) × multiplier;  Range = Resistance × (1 ± tolerance ÷ 100). Digits: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. Multiplier: 10^digit, gold × 0.1, silver × 0.01.
```

Where:
- Tolerance: brown ±1%, red ±2%, green ±0.5%, blue ±0.25%, violet ±0.1%, grey ±0.05%, gold ±5%, silver ±10%, no band ±20%

## Worked example
1. Brown = 1 and green = 5 give the digits 15.
2. Red multiplier = × 100, so 15 × 100 = 1,500 Ω = 1.5 kΩ.
3. Gold = ±5%: 1,500 × 0.05 = 75 Ω, so 1,425 to 1,575 Ω.

**Result:** Brown-green-red-gold is a 1.5 kΩ resistor with ±5% tolerance, anywhere from 1,425 Ω to 1,575 Ω.

## What the result means

Check a decoded value against the standard E-series (E12, E24…) values: if the result is not a standard value, you have probably read the bands from the wrong end. A multimeter settles any doubt.

## Assumptions and limits
- IEC 60062 colour code as commonly used for through-hole resistors.
- Grey and yellow tolerance markings vary between manufacturers and editions of IEC 60062 (grey is also used for ±0.01%); check the datasheet for precision parts.
- Surface-mount resistors use printed number codes, not colours.

## Questions

### Which end do I start from?

Start from the end with the band closest to the edge. The tolerance band, often gold or silver, is usually separated by a wider gap and goes last.

### What does a single black band mean?

A zero-ohm link: a jumper in a resistor body.

## Sources
- [Colorado State University ECE: Standard resistor colour code](https://www.engr.colostate.edu/ECE103/FA13/general%20info/Standard%20Resistor%20color%20code.htm)
- [TE Connectivity: Resistor colour codes](https://www.te.com/es/products/passive-components/resistors/intersection/resistor-color-codes.html)

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- [Ohm’s Law Calculator](https://calculators.geekmidst.com/calculators/ohms-law-calculator)
- [Voltage Drop Calculator](https://calculators.geekmidst.com/calculators/voltage-drop-calculator)

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/resistor-calculator