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Resistor color code

Read four or five bands, convert a value to colors and compare tolerances and E12, E24 and E96 nominal values.

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01 / Adjust the inputs

Sliders with a wide range use a logarithmic scale. When zero is allowed, it has its own position. Type a number to set an exact value.

Try an example

1234
  1. Band 1 · Yellow · Digit 1: 4
  2. Band 2 · Violet · Digit 2: 7
  3. Band 3 · Red · Multiplier: ×100
  4. Band 4 · Gold · Tolerance: ±5%

Numbers under the bands match the list. The separated final band on the right gives tolerance.

Represented nominal value4700 Ω
Tolerance minimum4465 Ω
Tolerance maximum4935 Ω

Read from the digits toward the tolerance band.

47 × 10² = 4700 Ω. ±5% interval: 4465 to 4935 Ω.

4700 Ω belongs to E24. Tolerance depends on its band.

Use it in your classroom

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From yellow and violet to 4.7 kΩ

The first two bands give 4 and 7. Red as the multiplier adds ×100: 47 × 100 = 4700 Ω. The final gold band means ±5%, or 235 Ω on either side of nominal. The permitted interval is 4465 to 4935 Ω; the resistor need not measure exactly 4700 Ω.

Now select five bands: red, orange, violet, black and brown. The digits form 237; black multiplies by 1 and the final brown band means ±1%. The result is 237 Ω, between 234.63 and 239.37 Ω.

To test reverse conversion, enter 237 Ω with four bands: only two significant digits fit. The tool reports an approximation of 240 Ω, a difference of about +1.26582%. Five bands represent 237 Ω exactly. Representation error and component tolerance are different concepts.

Digits, scale and interval

4 bands: R = (10a + b) × 10^m
5 bands: R = (100a + 10b + c) × 10^m
Rmin = R × (1 − tolerance/100)
Rmax = R × (1 + tolerance/100)

Reverse conversion keeps two or three significant digits and reports rounding. Crossing a decade also changes the multiplier: 999.6 Ω is represented approximately as 100 × 10 = 1000 Ω with five bands.

E12, E24 and E96 are nominal-value tables repeated by decade. The comparison shows whether a value belongs to the selected table or displays its neighbors. Selecting E96 does not change tolerance or guarantee stock availability. An E96 value may need five bands.

Supported codes

Four or five bands are supported, with a first digit from 1 to 9, multipliers from ×0.01 to ×1,000,000,000 and the eight listed tolerances. Nominal range is 0.1 Ω to 99 GΩ for four bands and 1 Ω to 999 GΩ for five. E-series suggestions are limited to 0.1 Ω…999 GΩ.

Six-band temperature-coefficient codes, zero-ohm resistors, SMD codes and multipliers outside this range are not supported. Screen colors are illustrative: lighting, aging and component type can make real bands ambiguous. Check the data sheet or measure appropriately out of circuit.

Common mistakes

  • Reading the tolerance band as another digit.
  • Confusing gold as a multiplier (×0.1) with gold as tolerance (±5%).
  • Always assigning five bands to a particular tolerance: read tolerance separately.
  • Rounding a nominal value without reporting the change from the requested value.

Quick guide: understand each band’s role

  1. Start with four bands and change only the multiplier. The number of digits stays the same.
  2. Change tolerance: the nominal value stays fixed while its bounds change.
  3. Switch to “Value → bands,” enter 237 Ω and compare four and five bands.
  4. Select E12, E24 and E96 to compare membership and neighboring values without changing the code being read.

Try it yourself

Red, red, brown, gold: what resistance does this represent?

22 × 10 = 220 Ω ±5%, between 209 and 231 Ω.

What do brown, black, silver and silver represent?

10 × 0.01 = 0.1 Ω ±10%, from 0.09 to 0.11 Ω. Silver means different things depending on its position.

Table references: Vishay resistor band code and Vishay resistor series, accessed October 25, 2026. Examples and exercises are original.