Resistor Color Code Decoder
Answer
Digits come from the first bands, then a multiplier band scales the value. The next band is tolerance (gold ±5%, silver ±10%). A sixth band, when present, is TCR in ppm/°C. Example: brown-black-red-gold is 1 kΩ ±5%.
Calculator
How it works
Through-hole resistors still ship with painted bands. The pattern is always significand digits, a multiplier, then tolerance; precision parts add another digit and sometimes TCR.
Pick the colours left to right. Leave optional bands empty for a 4-band decode. The calculator prints nominal resistance, tolerance percent, and min/max for a single part. Combine with the parallel resistor tool if you are synthesising a value from two preferred parts.
Parameters used on this page
| Parameter | Value | Source |
|---|---|---|
| 4-band value | (d1 d2) × multiplier | EIA / IEC colour code |
| 5-band value | (d1 d2 d3) × multiplier | Finer significand for 1% parts |
| Tolerance band | ±% from colour table | Manufacturer marking |
| Range | Rmin = R × (1 − tol), Rmax = R × (1 + tol) | Worst-case stack for a single part |
Worked example
Brown-black-red-gold: digits 1 and 0, multiplier red (×100) → 1000 Ω, gold → ±5%, so roughly 950 Ω–1050 Ω. Brown-black-black-red-brown is a 5-band 10.0 kΩ ±1%.
Pitfalls
- Reading the band closest to the edge as the multiplier. On many axials the tolerance band is slightly wider or separated — check the part photo.
- Forgetting that gold and silver are multipliers on 3-band legacy parts but tolerance on 4-band parts.
- Assuming a 6-band part always prints TCR you care about — still verify on the datasheet for precision networks.
FAQ
Which band is first on a 4-band resistor?
The first digit band is usually opposite the tolerance band. Gold or silver tolerance is often at the end of the code sequence.
What does brown-black-orange-gold mean?
10 × 1000 = 10 kΩ ±5%.
How do 5-band resistors differ?
They add a third digit before the multiplier, which helps 1% and 0.1% parts without awkward multipliers.
What is the sixth band?
Temperature coefficient (ppm/°C). The decoder shows it when you select six colours.
Related
Sources
- EIA RS-279 / IEC 60062 resistor colour code conventions.