Resistor Color Code Calculator
Decode 3-band, 4-band or 5-band resistor colour codes to ohms and tolerance. Select the number of bands and each colour to get the resistance instantly.
How to use this tool
- Enter number of bands, band 1 (1st digit), band 2 (2nd digit), band 3 (3rd digit / multiplier), band 4 (multiplier — 4-band), band 5 (multiplier — 5-band), band 6 (tolerance — 5-band) and band 5 (tolerance — 4-band) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your resistance and the full breakdown beneath it.
Resistor colour codes map coloured bands to resistance values. Each colour represents a digit 0–9, a multiplier or a tolerance. The most common 4-band resistor has: digit 1, digit 2, multiplier, tolerance (gold=±5%).
- Black=0, Brown=1, Red=2, Orange=3, Yellow=4, Green=5, Blue=6, Violet=7, Grey=8, White=9
- Gold multiplier=×0.1, Silver=×0.01
Formula
4-band: Resistance = (Band1 × 10 + Band2) × Multiplier(Band4)
5-band: Resistance = (Band1 × 100 + Band2 × 10 + Band3) × Multiplier(Band5)
3-band: Resistance = (Band1 × 10 + Band2) × Multiplier(Band3)
Tolerance is read from the final band using the standard IEC 60062 colour map.
How it works
Each colour band encodes a digit (0–9 for black–white) or a multiplier power of ten (plus gold ×0.1 and silver ×0.01). The significant-digit bands are combined into a base number, then multiplied by the multiplier band to give resistance in ohms.
The tolerance band is decoded separately using the standard colour-to-percentage table. Results are formatted automatically in Ω, kΩ, or MΩ for readability. The calculator assumes standard IEC 60062 colour coding; non-standard or military bands are not supported.
Worked example
Worked example — 4-band resistor
- Bands: Brown (1), Black (0), Red (multiplier ×100), Gold (tolerance ±5%).
- Significant digits: 1 × 10 + 0 = 10.
- Resistance = 10 × 100 = 1,000 Ω.
- Tolerance band Gold = ±5%.
Resistance: 1000 Ω | Tolerance: ±5%
Key terms
- Colour Band
- A coloured stripe printed on a resistor body that encodes a digit, multiplier, or tolerance value according to the IEC 60062 standard.
- Multiplier Band
- The band that specifies the power-of-ten factor by which the significant digits are multiplied to give the final resistance.
- Tolerance
- The permissible deviation from the nominal resistance, expressed as a percentage (e.g., ±5% gold, ±1% brown).
- Significant Digits
- The first two (4-band) or three (5-band) colour bands that form the base number before the multiplier is applied.
- IEC 60062
- The international standard that defines the colour coding system for resistors, capacitors, and inductors.
Frequently asked questions
- How do I read a 4-band resistor?
- Read bands left to right. The first two give the first two digits, the third is the multiplier and the fourth is tolerance. Brown-Black-Red-Gold = 10 × 100 = 1000 Ω ±5%.
- What does a 5-band resistor add?
- A 5-band resistor adds a third significant digit before the multiplier, giving higher precision. It is common on 1% tolerance resistors.
- Why is there a gap before the tolerance band?
- Manufacturers leave a larger gap before the tolerance band so you can tell which end to start reading from.