Resistors are too small to print numbers on, so the value is painted in coloured bands. The system is over seventy years old and completely unambiguous — provided you start from the correct end.
The colour chart
One table covers everything:
| Colour | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Black | 0 | ×1 | — |
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1,000 | — |
| Yellow | 4 | ×10,000 | — |
| Green | 5 | ×100,000 | ±0.5% |
| Blue | 6 | ×1,000,000 | ±0.25% |
| Violet | 7 | ×10,000,000 | ±0.1% |
| Grey | 8 | — | ±0.05% |
| White | 9 | — | — |
| Gold | — | ×0.1 | ±5% |
| Silver | — | ×0.01 | ±10% |
The digit column and the multiplier column follow the same order, which is the part worth internalising: the multiplier band is just "how many zeros to add". Orange in a multiplier position means three zeros, because orange is 3.
The resistor colour code calculator does this both ways — bands to value, and value back to bands.
4-band vs 5-band
The difference is one significant figure.
4-band — digit, digit, multiplier, tolerance. Standard tolerances of ±5% (gold) or ±10% (silver). These are the common, cheap resistors.
5-band — digit, digit, digit, multiplier, tolerance. The extra digit gives precision, and the tolerance band is usually brown (±1%) or red (±2%). These are precision parts.
You can tell them apart by counting bands, but there is a faster tell: if the tolerance band is gold or silver, it is a 4-band. Gold and silver are almost never used as digits, because there is no digit they correspond to.
Which end do you start from?
This is the only genuinely difficult part, and it trips up beginners constantly.
Three rules, in order of reliability:
1. The tolerance band usually has a wider gap before it. Manufacturers group the value bands together and leave a gap before the tolerance band. Hold the resistor so the gap is on your right. 2. Gold or silver means tolerance, and tolerance goes last. If you see gold or silver at one end, that end is the right-hand end. 3. Start from the end with a band closest to the lead. The value bands are shifted toward one end; the tolerance band sits further in.
If none of these help — some resistors are genuinely ambiguous — read it both ways and see which gives a sensible value. Resistors come in standard E-series values, so one direction will usually produce a common value like 4.7 kΩ and the other something implausible like 7.4 kΩ.
Worked example: a 4-band resistor
Bands: yellow, violet, red, gold
- Yellow = 4 (first digit)
- Violet = 7 (second digit)
- Red = ×100 (multiplier)
- Gold = ±5% (tolerance)
47 × 100 = 4,700 Ω = 4.7 kΩ, ±5%
The ±5% means the real value is somewhere between 4,465 Ω and 4,935 Ω. That is normal and usually irrelevant — but it matters in a timing circuit, where the tolerance propagates directly into the frequency.
Worked example: a 5-band resistor
Bands: brown, black, black, brown, brown
Four brown bands makes this look confusing, but the positions do the work:
- Brown = 1 (first digit)
- Black = 0 (second digit)
- Black = 0 (third digit)
- Brown = ×10 (multiplier)
- Brown = ±1% (tolerance)
100 × 10 = 1,000 Ω = 1 kΩ, ±1%
Note that the same 1 kΩ resistor as a 4-band part would be brown, black, red, gold. The 5-band version buys you a tighter tolerance, not a different value.
Why the values look arbitrary
Resistors come in E-series: E12 has twelve values per decade (10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82), E24 has twenty-four, E96 has ninety-six.
The values are spaced logarithmically so that consecutive values differ by roughly the tolerance. With ±10% parts, twelve values per decade means any target value is within tolerance of a stocked one. That is why 4.7 kΩ is everywhere and 5 kΩ essentially does not exist.
Common mistakes
- Reading it backwards. Yellow-violet-red-gold is 4.7 kΩ. Read from the wrong end, gold-red-violet-yellow is not a valid code at all — which is itself the clue that you have it reversed.
- Confusing brown and red under poor light. Both are dark. This is the most common misread, and it is a factor-of-ten error if it lands in the multiplier position. Check under daylight.
- Assuming a black multiplier means zero ohms. Black as a multiplier is ×1, not ×0. A single black band all by itself means a zero-ohm link, which is a different thing.
- Forgetting tolerance in a divider. Two ±5% resistors in a voltage divider give an output that can be off by nearly 10% in the worst case. Use ±1% parts where the ratio matters.
- Trusting the colour on a burnt resistor. Overheating discolours the body and the bands. If it looks scorched, measure it rather than reading it.
Frequently asked questions
What if there are only three bands?
Three bands means ±20% tolerance — the tolerance band is simply omitted. These are rare now.
What does a 6-band resistor mean?
The sixth band is the temperature coefficient in ppm/°C. It matters in precision analogue work and can be ignored otherwise.
Can I just measure it with a multimeter?
Yes, and you should when it matters. But measure it **out of circuit** — parallel paths in the board will read low.
Does band order depend on the manufacturer?
No, the standard (IEC 60062) is universal. Only the physical spacing that hints at direction varies.
How do I go from a value back to bands?
The [resistor calculator](/resistor-color-code) does the reverse lookup, which is handy when you are picking a part from a drawer.
Related reading
Once you have the resistance, the next question is usually current or power. The Ohm's law calculator solves for voltage, current, resistance or power from any two known values — useful for checking a resistor is rated for the power it will dissipate.