How to Read a Resistor Color Code (Bands to Ohms)

A resistor is too small to print a number on, so its value is written in colored bands, a code that looks cryptic until you know the trick. Once you do, you can read any resistor at a glance: the first bands are digits, the next multiplies them, and the last tells you how precise it is.

The color-to-number table

The heart of it is a single mapping from color to digit, easy to remember once and use forever:

Color	Digit	As multiplier
Black	0	×1
Brown	1	×10
Red	2	×100
Orange	3	×1 k
Yellow	4	×10 k
Green	5	×100 k
Blue	6	×1 M
Violet	7	×10 M
Grey	8	,
White	9	,

Plus two fractional multipliers for small resistors: Gold ×0.1 and Silver ×0.01.

A quick way to lock the sequence into memory is to notice that after black (0) the colors follow the order of a rainbow, red, orange, yellow, green, blue, violet, bracketed by brown at the bottom and grey then white at the top. Many people learn it with a mnemonic; the exact wording matters less than reciting it until the color-to-digit jump is automatic. Once it is, the whole reading process is just “digit, digit, count the zeros, check the tolerance.”

Reading a 4-band resistor

The classic resistor has four bands. Reading from the grouped end:

1. First band, the first digit.
2. Second band, the second digit.
3. Third band, the multiplier (how many zeros to add).
4. Fourth band, the tolerance.

So Brown-Black-Red-Gold is: 1 (brown), 0 (black), ×100 (red) → 1000 Ω = 1 kΩ, at ±5% (gold). A 1 kΩ ±5% resistor is guaranteed to fall between 950 Ω and 1,050 Ω.

A few more worked examples

Working through several codes makes the pattern stick. In each case, read the first two colors as digits, treat the third as the number of zeros to append, and the fourth as the tolerance.

Bands	Digits	Multiplier	Value	Tolerance
Yellow-Violet-Brown-Gold	4, 7	×10	470 Ω	±5%
Brown-Black-Orange-Gold	1, 0	×1 k	10 kΩ	±5%
Red-Red-Red-Silver	2, 2	×100	2.2 kΩ	±10%
Green-Blue-Yellow-Gold	5, 6	×10 k	560 kΩ	±5%
Brown-Black-Gold-Gold	1, 0	×0.1	1.0 Ω	±5%

The last row shows the fractional multiplier in action: a gold third band means “multiply by 0.1,” so brown-black gives 10, then 10 × 0.1 = 1.0 Ω. That example is worth pausing on, because a gold or silver band in the third position is easy to misread as tolerance. Position, not just color, decides what a band means.

Which end do I start from?

This is the one thing beginners get wrong. Read from the end where the bands are grouped closest together; the tolerance band is slightly separated and comes last. If you can’t tell, the tolerance band is usually the odd one out, a gold or silver band, or the one with a visible gap before it. Read a resistor backwards and you’ll get a wildly different (and wrong) value, so it’s worth checking.

Two quick sanity checks help when a resistor is genuinely ambiguous. First, a resistor’s first digit band is never black, because a value can’t start with a leading zero, so if one end starts with black, you’re reading from the wrong end. Second, if you get a value that isn’t a standard part (see the common-values note below), you’ve probably reversed it. When both ends look plausible, measure it with a multimeter and let the number settle the argument.

What the tolerance band tells you

Tolerance is the manufacturer’s promise about how close the real resistance is to the printed value. It does not mean the part is “off”. It means any resistor in that batch could sit anywhere inside the guaranteed window. The tighter the tolerance, the more the manufacturer sorted and tested, and the more you pay.

Tolerance color	Tolerance	Typical use
Silver	±10%	Non-critical, older parts
Gold	±5%	General-purpose hobby and consumer
Brown	±1%	Precision, most modern 5-band parts
Red	±2%	Precision
Green	±0.5%	High precision
Blue	±0.25%	High precision
Violet	±0.1%	Reference / measurement
(no band)	±20%	Legacy, now rare

For a 1 kΩ resistor, that spread is concrete: at ±5% the true value lives between 950 Ω and 1,050 Ω, but at ±1% it is pinned to 990 Ω to 1,010 Ω. For most digital, lighting, and pull-up work the wider tolerance is invisible. For voltage dividers, filters, and timing networks, the tighter band earns its cost.

5-band and 6-band resistors

Precision resistors add bands. A 5-band resistor has three digit bands before the multiplier, giving an extra significant figure (so a value like 4.7 kΩ can be marked exactly), usually at a tight ±1% tolerance. A 6-band resistor adds one more: a temperature coefficient, in parts per million per °C, telling you how much the resistance drifts as it heats up, important for precision analog and measurement circuits.

Reading a 5-band part is the same routine with one extra digit. Brown-Green-Black-Red-Brown is 1, 5, 0 for the digits, ×100 for the multiplier, so 150 × 100 = 15,000 Ω = 15 kΩ, at ±1% (brown). Note how the same physical value can appear as either a 4-band or 5-band part, the 5-band version just carries the extra significant figure the tighter tolerance implies.

The band-count differences line up like this:

Bands	Layout	Typical tolerance	Extra info
4-band	digit, digit, multiplier, tolerance	±5% / ±10%	,
5-band	digit, digit, digit, multiplier, tolerance	±1%	Extra significant figure
6-band	digit, digit, digit, multiplier, tolerance, tempco	±1% or tighter	Temperature coefficient (ppm/°C)

Common values you’ll actually meet

Resistors aren’t made in every possible value. They come in standardized “E-series” steps chosen so that, allowing for tolerance, the ranges tile the number line without big gaps. The ±5% E24 series and ±10% E12 series cover most hobby needs. That’s why values like 220 Ω, 330 Ω, 470 Ω, 1 kΩ, 2.2 kΩ, 4.7 kΩ and 10 kΩ turn up again and again: they’re standard steps, repeated across every decade by shifting the multiplier band. If you decode a resistor and land on an oddball number like 1.37 kΩ from a 4-band part, it’s a strong hint you read the bands in the wrong order.

Just read it for me

Memorising the code is handy, but you don’t have to. The resistor color code calculator lets you pick each band’s color from a menu and shows the resistance, tolerance and range instantly, with a live picture of the resistor so you can match it to the part in your hand. It handles 4, 5 and 6-band resistors, and like every LazyTools tool it runs entirely in your browser. Building a circuit around it? The LED resistor calculator sizes the resistor an LED needs, and the capacitor code calculator decodes the matching capacitor markings.

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Values follow the IEC 60062 resistor color code. Tolerance gives the guaranteed range around the nominal value; the ultra-tight tolerance-band colors (used on precision parts) vary slightly between references, so check the datasheet for critical applications.