Resistor decoder.
Pick band colors, get resistance. Or work backwards from a target value.
→ —
How resistor color codes actually work
Read left to right
The end with bands packed closer is the start. The lone band at the other end is usually tolerance.
Digits, then multiplier
The first 2 (or 3) bands are digits 0–9. The next band is the multiplier — how many zeros to add.
Last band is tolerance
Gold = ±5%, silver = ±10%, brown = ±1%. Most modern resistors are 5% or 1%.
| COLOR | DIGIT | MULTIPLIER | TOLERANCE | TEMPCO (ppm/K) |
|---|---|---|---|---|
| BLACK | 0 | ×1 | — | — |
| BROWN | 1 | ×1e1 | ±1% | 100 |
| RED | 2 | ×1e2 | ±2% | 50 |
| ORANGE | 3 | ×1e3 | — | 15 |
| YELLOW | 4 | ×1e4 | — | 25 |
| GREEN | 5 | ×1e5 | ±0.5% | — |
| BLUE | 6 | ×1e6 | ±0.25% | 10 |
| VIOLET | 7 | ×1e7 | ±0.1% | 5 |
| GREY | 8 | ×1e8 | ±0.05% | — |
| WHITE | 9 | ×1e9 | — | — |
| GOLD | — | ×0.1 | ±5% | — |
| SILVER | — | ×0.01 | ±10% | — |
Related reading: Reading resistor color codes → · SMD resistor code calculator →
Reading a resistor, start to finish
A resistor color code is a row of painted bands that encodes the part's resistance: two or three digit bands, one multiplier band, one tolerance band, and on 6-band parts a temperature coefficient band in ppm/K.
The maths is one line: R = digits × multiplier, and the real part can sit
anywhere in R × (1 − tol/100) to R × (1 + tol/100).
Example. A 4-band resistor reads yellow, violet, red, gold. Yellow is 4
and violet is 7, so the digits are 47. Red multiplies by 100, giving
47 × 100 = 4,700 Ω (4.7 kΩ). Gold in the last position is ±5%, so
anything from 4,465 Ω to 4,935 Ω is in spec.
Gotcha: brown at both ends. Brown is both the digit 1 and the ±1%
tolerance color, and 5-band parts are usually 1%. Brown, black, black, brown, brown reads
100 × 10 = 1 kΩ ±1% one way and 110 × 1 = 110 Ω ±1% the other.
The tolerance band normally has a wider gap before it; if you can't see one, measure the
part with a multimeter before you solder it.
Questions people actually ask
Which end of a resistor do I start reading from?
Start at the end where the bands are bunched together. The tolerance band, often gold or silver, usually sits alone at the other end with a wider gap before it. If both ends look the same, a multimeter settles it in a few seconds.
What does a gold band mean on a resistor?
It depends on its position. In the tolerance position gold means ±5%. In the multiplier position gold means ×0.1, so red, red, gold, gold is 22 × 0.1 = 2.2 Ω at ±5%.
What is the difference between 4, 5 and 6-band resistors?
A 4-band resistor has two digits, a multiplier and a tolerance band, and is typical of 5% parts. A 5-band resistor adds a third digit for precision parts of 1% or better. A 6-band resistor adds a sixth band for temperature coefficient, how far the value drifts per kelvin, in ppm/K.
What are the color bands for a 10k resistor?
On a 4-band 5% part: brown, black, orange, gold (10 × 1,000 = 10 kΩ). On a 5-band 1% part: brown, black, black, red, brown (100 × 100 = 10 kΩ).
What are the color bands for a 220 ohm resistor?
On a 4-band 5% part: red, red, brown, gold (22 × 10 = 220 Ω). On a 5-band 1% part: red, red, black, black, brown (220 × 1 = 220 Ω).
Can I get the colors from a resistance value?
Yes. Type the value into the target-value box under the band picker and choose a tolerance; the drawing shows the bands for the current 4, 5 or 6-band mode. Values are rounded to 2 significant digits in 4-band mode and 3 in 5 and 6-band mode.