How to read the bands
Read a resistor from the end where the bands are closest together. The last band, separated by a wider gap, is the tolerance band.
- 4-band: first digit, second digit, multiplier, tolerance. So brown-black-red-gold is 1, 0, times 100, plus or minus 5% — 1,000 ohms, or 1k.
- 5-band: three significant digits, then multiplier, then tolerance. Used for precision resistors, typically 1% or better.
- 6-band: as 5-band, plus a temperature coefficient band at the end.
Higher-band-count resistors are not automatically more accurate — the count tells you how many digits are specified. A 5-band resistor with a 5% gold tolerance band is still a 5% part.
The complete colour table
| Colour | Digit | Multiplier | Tolerance | Temp. coeff. |
|---|---|---|---|---|
| Black | 0 | ×1 | — | — |
| Brown | 1 | ×10 | ±1% | 100 ppm/K |
| Red | 2 | ×100 | ±2% | 50 ppm/K |
| Orange | 3 | ×1k | — | 15 ppm/K |
| Yellow | 4 | ×10k | — | 25 ppm/K |
| Green | 5 | ×100k | ±0.5% | — |
| Blue | 6 | ×1M | ±0.25% | 10 ppm/K |
| Violet | 7 | ×10M | ±0.1% | 5 ppm/K |
| Grey | 8 | — | ±0.05% | — |
| White | 9 | — | — | — |
| Gold | — | ×0.1 | ±5% | — |
| Silver | — | ×0.01 | ±10% | — |
Gold and silver appear only as multipliers or tolerance bands, never as digit bands. That is useful when you are trying to work out which end to read from.
Two worked examples
1. A common 1% metal film resistor
Bands brown-black-black-brown-brown: digits 1 and 0, then a third digit of 0, giving 100, multiplied by 10 to give 1,000 ohms, with a brown tolerance of 1%. That is 1k at 1%. Note how the same nominal value appears differently on a 4-band part (brown-black-red-gold, 1k at 5%), which is why the band count matters when you are reading a part in your hand.
2. A 4.7k pull-up resistor
Bands yellow-violet-red-gold: 4, 7, times 100, plus or minus 5% — 4,700 ohms at 5%. The tolerance band of gold is the giveaway that this is a standard 4-band part. Its actual value lies between 4,465 and 4,935 ohms, which for a pull-up resistor is perfectly acceptable.
Standard values: why 4.7k and not 4.6k
Resistors are manufactured in preferred number series rather than at every conceivable value. The E24 series defines 24 values per decade and covers 5% parts; E96 defines 96 values per decade for 1% parts. The values are spaced so that the tolerance bands of adjacent parts just touch, which means any required value is always close to a stocked one.
The E24 values in each decade are 10, 11, 12, 13, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 39, 43, 47, 51, 56, 62, 68, 75, 82 and 91. Multiply by a power of ten to get any practical value. If your calculation lands between two of these, the calculator tells you the nearest one and by how much it differs.
Reading a resistor in practice
- Identify the tolerance band first. It is usually separated by a wider gap and is often gold, silver or brown. Everything else reads away from that end.
- Beware of colour ambiguity. Brown, red and orange are hard to separate on a small body, and so are blue and violet. If in doubt, measure the part with a multimeter.
- Measure before trusting. A resistor in circuit can read lower than its true value because parallel paths conduct around it. Lift one leg to measure accurately.
- Heat changes colour. A discoloured body suggests the part has been running hot, which usually means the wattage rating was too low.
How this calculator is verified
The colour assignments follow IEC 60062, the international standard for marking codes on resistors and capacitors. The preferred value series follow IEC 60063 for E24 and E96. Both are reproduced here for the bands commonly found on through-hole parts.
- IEC 60062 — marking codes for resistors and capacitors, including the colour code.
- IEC 60063 — preferred number series for resistors and capacitors (E-series).
- NIST — SI unit definitions used for the resistance values shown.
Colour table and worked examples last verified: 19 September 2026.
Tools for reading and checking resistors
Bands are easy to misread on a small body, and a resistor in circuit reads differently from its markings. These are the tools that close that gap.
- Digital multimeter — The page says measure before trusting. A multimeter is the check on the bands, especially where brown, red and orange are hard to separate.
- Jeweler’s loupe — A small body under poor light is where the wrong band gets read. A loupe or bench magnifier separates the colours before you confuse brown with red.
- Resistor assortment kit — For finding the nearest stocked value in the E24 and E96 series without ordering singles.
- Solderless breadboard — A resistor measured in circuit can read low. A breadboard lets you check the part on its own against its bands.
As an Amazon Associate I earn from qualifying purchases. The links above are affiliate links — if you buy through one, the price you pay is unchanged and a small commission helps keep these calculators free. Tools are listed because the job calls for them, not because of commission rates.