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Calculator

Resistor Color Code Calculator

Decode 4, 5 and 6-band resistors — or find the bands for any value.

Result

Resistor with 4 colour bands

0 Ω ±1%

Real value is between
0 Ω – 0 Ω
In ohms
0 Ω

Going the other way: value to colour bands

Type a resistance in ohms (for example 4700 for 4.7 kΩ) to see its 4-band colours.

Ω
Resistor with 4 colour bands

Yellow · Violet · Red · Gold (±5%)

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How it works

Resistors are too small to print numbers on, so they wear coloured bands instead. Each colour stands for a digit, a multiplier or a tolerance. This calculator reads the bands for you: choose the colours from your resistor and it shows the resistance, tolerance and the range it should measure in.

Hold the resistor with the tolerance band (usually gold or silver) on the right. Read left to right. 4-band resistors have two digits, a multiplier and a tolerance; 5-band precision resistors have three digits; 6-band parts add a temperature coefficient.

Formula

4-bandR = (10 × D1 + D2) × Multiplier ± Tolerance
5-bandR = (100 × D1 + 10 × D2 + D3) × Multiplier ± Tolerance
RangeR(min…max) = R × (1 − tol%) … R × (1 + tol%)

Worked example. Brown, black, red, gold = 1, 0 × 100 = 1,000 Ω (1 kΩ) ±5%. The real resistor should measure between 950 Ω and 1,050 Ω.

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Frequently asked questions

Which end do I start reading from?

Start from the end with the bands closest together. The tolerance band (gold, silver, or sometimes brown) sits a little apart on the right-hand side. If the first band is gold or silver, you are reading it backwards.

What do the gold and silver bands mean?

In the tolerance position, gold means ±5% and silver means ±10%. In the multiplier position, gold means ×0.1 and silver means ×0.01, which is how values below 10 Ω are written.

How do I tell a 4-band from a 5-band resistor?

Count the bands. Four bands: two digits, multiplier, tolerance. Five bands: three digits, multiplier, tolerance — usually a thin, blue-ish metal-film resistor with 1% tolerance. Always confirm with a multimeter if it matters.

Why does my multimeter show a slightly different value?

Resistors are only guaranteed to be within their tolerance. A 5% resistor marked 1 kΩ can measure anywhere from 950 Ω to 1,050 Ω. Also, measuring in-circuit gives wrong readings because other parts are connected in parallel.

Boards this helps with

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