Resistor Color Code Calculator
Decode 4, 5 and 6-band resistor colour codes to resistance, tolerance, min/max value and temperature coefficient, using the IEC 60062 colour table.
Resistor Color Code Calculator: with the default inputs, resistance is 1 kΩ ±5%.
Count the bands with the tolerance band (usually gold or silver, and set slightly apart) on the right.
5 and 6-band resistors only; ignored on a 4-band part.
6-band resistors only; ignored otherwise.
Nominal value with the usual engineering prefix.
- Resistance (Ω)
- 1,000
- Tolerance
- 5%
- Minimum value (Ω)
- 950
- Maximum value (Ω)
- 1,050
- Guaranteed range
- 0.95 kΩ to 1.05 kΩ
- Temperature coefficient (ppm/K)
- —
Assumptions
- Colour values follow IEC 60062:2016; a few manufacturers use extra tolerance colours not in the standard.
- The nominal value is specified at 25 °C with no self-heating.
- Tolerance is applied symmetrically about the nominal value.
| Colour | Digit | Multiplier | Tolerance | Temp. coeff. |
|---|---|---|---|---|
| Black | 0 | ×1 | — | 250 ppm/K |
| Brown | 1 | ×10 | ±1% | 100 ppm/K |
| Red | 2 | ×100 | ±2% | 50 ppm/K |
| Orange | 3 | ×1,000 | — | 15 ppm/K |
| Yellow | 4 | ×10,000 | — | 25 ppm/K |
| Green | 5 | ×100,000 | ±0.5% | 20 ppm/K |
| Blue | 6 | ×1,000,000 | ±0.25% | 10 ppm/K |
| Violet | 7 | ×10,000,000 | ±0.1% | 5 ppm/K |
| Grey | 8 | ×100,000,000 | ±0.05% | 1 ppm/K |
| White | 9 | ×1,000,000,000 | — | — |
| Gold | — | ×0.1 | ±5% | — |
| Silver | — | ×0.01 | ±10% | — |
| Pink | — | ×0.001 | — | — |
| None | — | — | ±20% | — |
Your bands: Brown – Black – Red – Gold. A dash means the colour is not used in that column.
How this is worked out
The formula
4-band: R = (d1×10 + d2) × multiplier, ±tolerance 5/6-band: R = (d1×100 + d2×10 + d3) × multiplier, ±tolerance min = R × (1 − tol/100) max = R × (1 + tol/100) 6th band = temperature coefficient in ppm/K: drift = R × ppm × ΔT ÷ 1,000,000
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Number of bands
- Count the bands with the tolerance band (usually gold or silver, and set slightly apart) on the right.4 bands (2 digits, multiplier, tolerance) · 5 bands (3 digits, multiplier, tolerance) · 6 bands (3 digits, multiplier, tolerance, temp. coefficient)
- Band 1 — first digit
- Choose one of 10 options.Black · Brown · Red · Orange · Yellow · Green · Blue · Violet · Grey · White
- Band 2 — second digit
- Choose one of 10 options.Black · Brown · Red · Orange · Yellow · Green · Blue · Violet · Grey · White
- Band 3 — third digit
- 5 and 6-band resistors only; ignored on a 4-band part.Black · Brown · Red · Orange · Yellow · Green · Blue · Violet · Grey · White
- Multiplier band
- Choose one of 13 options.Black · Brown · Red · Orange · Yellow · Green · Blue · Violet · Grey · White · Gold · Silver · Pink
- Tolerance band
- Choose one of 9 options.Brown · Red · Green · Blue · Violet · Grey · Gold · Silver · None (no band)
- Temperature coefficient band
- 6-band resistors only; ignored otherwise.Black · Brown · Red · Orange · Yellow · Green · Blue · Violet · Grey
What you get back
- Resistancemain answer
- Nominal value with the usual engineering prefix.
- Resistance (Ω)
- Tolerance
- Minimum value (Ω)
- Maximum value (Ω)
- Guaranteed range
- Temperature coefficient (ppm/K)
What this assumes
- Colour values follow IEC 60062:2016; a few manufacturers use extra tolerance colours not in the standard.
- The nominal value is specified at 25 °C with no self-heating.
- Tolerance is applied symmetrically about the nominal value.
About this calculator
Through-hole resistors are too small to print a number on, so the value is painted on in coloured rings. Pick the number of bands and the colour of each one and this decodes the nominal resistance, the tolerance, the range the manufacturer actually guarantees, and — on a 6-band part — how far the value drifts as the resistor heats up.
Reading the bands in the right order
The single most common mistake is reading the resistor backwards. Two things tell you which end is which: the tolerance band is set slightly further from the others, and it is usually gold or silver, colours that never appear as a first digit. So put gold/silver on the right and read left to right. If your reading starts with black, you are almost certainly holding it the wrong way round — a first band of black would mean a leading zero, which nobody manufactures.
On a 4-band part the first two bands are digits and the third is the power-of-ten multiplier. On 5 and 6-band parts there are three digit bands, which is how precision resistors express values like 4.99 kΩ. The extra sixth band is the temperature coefficient.
What tolerance actually buys you
Gold is ±5%, silver ±10%, and no fourth band at all means ±20%. Brown (±1%) and red (±2%) are the metal-film precision range. Tolerance is not a statistical hint, it is a guarantee: a 1 kΩ ±5% part is sold as being between 950 Ω and 1,050 Ω, and the distribution inside that window is whatever the factory's yield sorting left behind — often bimodal, because the closer-tolerance parts have been picked out and sold at a higher grade.
Where the colour code stops working
- Faded and burnt parts. Heat cooks red into brown and orange into brown; a resistor that has been overloaded may be unreadable and out of spec anyway. Measure it.
- Surface-mount parts use a printed numeric code (473 = 47 × 10³ = 47 kΩ), not colours.
- Colour blindness and cheap ink. Red/brown and violet/blue are genuinely hard to tell apart under warm light. When it matters, confirm with a meter.
- The value on the band is the value at 25 °C, unloaded. A resistor dissipating real power sits well above ambient, and with a 100 ppm/K part a 50 K rise shifts a 1 kΩ resistor by 5 Ω — more than a 1% part's whole tolerance budget.
- Zero-ohm links carry a single black band and are not a colour code at all.
Values also cluster on the E-series (E12 for ±10%, E24 for ±5%, E96 for ±1%), so if your decode lands on something like 1.37 kΩ in a 4-band part, re-read the bands.
Frequently asked questions
▸What resistor is brown, black, red, gold?
1 kΩ ±5%. Brown = 1 and black = 0 give 10, red multiplies by 100, and gold is the ±5% tolerance band — so anything from 950 Ω to 1,050 Ω.
▸Which end do I start reading from?
The end whose band is closest to the lead, with the tolerance band (usually gold or silver, and spaced slightly apart) last. If the first band reads black, turn the resistor round.
▸What is the difference between a 4-band and a 5-band resistor?
A 5-band part has three significant digits instead of two, so it can express precision values such as 4.99 kΩ. The last two bands still mean multiplier and tolerance.
▸What does the sixth band mean?
Temperature coefficient in ppm/K — how much the resistance changes per kelvin. Brown is 100 ppm/K, so a 10 kΩ resistor drifts 1 Ω for every degree of temperature rise.
▸My measured value is outside the tolerance. What happened?
Either you misread a band, the resistor has been overheated (which permanently shifts the value), or your meter is including lead and probe resistance — significant when the part is under about 10 Ω.
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