Resistor Color Code Chart and a Mnemonic That Works • The Science 360

Ten colours carry ten digits, and seven of them are already in your head in the right order. Red, orange, yellow, green, blue, violet: the rainbow you learned as a child is the resistor color code for 2 to 7. You only have to memorise four more colours, two at each end, and the whole code falls into place. That is the mnemonic that works, and this post builds the rest of the system around it.

Below is the full chart, the rules for 4, 5 and 6 band resistors, and a table of the values you will actually meet. If you want to check a part while you read, the resistor color code calculator lets you tap each band to change its colour, or type a value like 4k7 and see its bands.

Quick answerBlack 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. On a 4 band resistor read two digits, then the multiplier (number of zeros), then the tolerance: gold ±5%, silver ±10%, brown ±1%. Yellow, violet, red, gold is 47 with two zeros, 4.7 kΩ ±5%.

Resistor color code chart for 4, 5 and 6 band resistors (IEC 60062): black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9, with multipliers from x0.001 to x1 G, tolerances gold 5%, silver 10%, brown 1%, red 2%, and temperature coefficients from 250 to 1 ppm/K — Figure 1. The full colour code chart from IEC 60062, with the bands of a 4.7 kΩ resistor highlighted: yellow 4, violet 7, red ×100, gold ±5%. Open the chart in the simulator.

What is the mnemonic for the resistor color code?

Split the ten colours into three groups:

Two dark colours first: black 0, brown 1. Dark comes before light, and black is darker than brown.
The rainbow in the middle: red 2, orange 3, yellow 4, green 5, blue 6, violet 7. This is ROY G BV, the rainbow without indigo.
Two pale colours last: grey 8, white 9. Grey before white, the way dark comes before light.

If you want one sentence, use "B B ROY of Great Britain has a Very Good Wife": black, brown, red, orange, yellow, green, blue, violet, grey, white. It works because the middle of it is the rainbow you already know, so you only need the sentence for the ends. Many older mnemonics for this code are crude or offensive; you do not need them.

Two more anchors help when you are reading a real part. Brown is 1 and red is 2, so a brown or red final band on a precision resistor reads ±1% or ±2%, the same digits. And the multiplier band is simply the number of zeros to write after the digits: orange is 3, so three zeros.

How do you read a 4 band resistor?

Turn the resistor so the bunched-up bands are on the left and the band set apart (usually gold or silver) is on the right. Then read left to right: digit, digit, multiplier, tolerance.

Example 1: yellow, violet, red, gold

\begin{aligned}\text{digits} &= 4,\ 7 \;\Rightarrow\; 47 \\ R &= 47 \times 10^{2} = 4700\ \Omega = 4.7\ \text{k}\Omega \\ \text{range} &= 4700 \times (1 \pm 0.05) = 4465\ \text{to}\ 4935\ \Omega\end{aligned}

Red as the third band means two zeros, not the digit 2. Gold at the end is ±5%, so any part that measures between 4.465 kΩ and 4.935 kΩ is in spec. On schematics this value is often written 4K7, with the letter where the decimal point would be.

4.7 kilohm resistor with yellow, violet, red and gold bands: 4, 7, multiplier x100, tolerance plus or minus 5 percent, so 4.465 to 4.935 kilohms, a standard E6 value — Figure 2. Yellow, violet, red, gold decoded band by band: 4, 7, ×100, ±5%, giving 4.7 kΩ with a range of 4.465 kΩ to 4.935 kΩ. Open this resistor in the simulator.

The most common mistake is treating the third band as a digit. Red, red, brown, gold is 22 with one zero, 220 Ω, not 221 Ω. A quick sanity check catches this every time: real resistors only come in standard values, and 221 Ω is not one of them in the 5% range.

220 ohm resistor with red, red, brown and gold bands: digits 2 and 2, brown multiplier x10, gold tolerance 5 percent, range 209 to 231 ohms — Figure 3. Red, red, brown, gold: the brown third band means one zero, so 220 Ω, with a ±5% range of 209 Ω to 231 Ω. Open this resistor in the simulator.

Which end of a resistor do you read first?

Start at the end where the bands are closer to the edge and to each other. The tolerance band usually has a slightly wider gap before it. Two rules settle most doubtful cases. First, gold and silver are never a first digit, so if one end is gold or silver, that end is the tolerance. Second, only one direction usually gives a standard value: brown, black, orange, gold read forwards is 10 kΩ, read backwards it starts with gold, which is impossible.

The hard case is a 5 band precision part with brown at both ends, such as brown, black, black, brown, brown (1 kΩ ±1%). Read backwards it gives brown, brown, black, black: 110 Ω, which also exists. Look closely for the gap, and if you still cannot tell, measure it. A multimeter costs less than a debugging evening.

How do 5 band and 6 band resistors differ?

A 5 band resistor has three significant digits before the multiplier, so it can mark values like 4.99 kΩ or 1.02 kΩ that two digits cannot. These are usually 1% metal film parts on a blue body, and they use the E96 series of 96 values per decade.

Example 2: brown, black, black, brown, brown

\begin{aligned}\text{digits} &= 1,\ 0,\ 0 \;\Rightarrow\; 100 \\ R &= 100 \times 10^{1} = 1000\ \Omega \\ \text{range} &= 1000 \times (1 \pm 0.01) = 990\ \text{to}\ 1010\ \Omega\end{aligned}

Notice the multiplier is brown (×10) here, while on a 4 band 1 kΩ (brown, black, red) it is red (×100). The extra digit takes one of the zeros.

5 band 1 kilohm precision resistor on a blue body with brown, black, black, brown, brown bands: digits 1 0 0, multiplier x10, tolerance plus or minus 1 percent, range 990 to 1010 ohms — Figure 4. A 5 band 1 kΩ, 1% resistor: three digits (1, 0, 0), a ×10 multiplier and a brown ±1% tolerance band. Open this resistor in the simulator.

A 6 band resistor is a 5 band code with one more band at the end for the temperature coefficient, how much the resistance moves per degree. Brown is 100 ppm/K, red 50, yellow 25, orange 15, blue 10 and violet 5.

Example 3: how much does a 6 band resistor drift?

Brown, black, black, orange, brown, red is 100 × 1000 = 100 kΩ, ±1%, 50 ppm/K. Over a 50 °C rise:

\Delta R = 100\,000\ \Omega \times 50 \times 10^{-6}\ \text{K}^{-1} \times 50\ \text{K} = 250\ \Omega

That is 0.25%, a quarter of the tolerance. It matters in measurement circuits and precision filters, and almost nowhere else.

6 band 100 kilohm resistor with brown, black, black, orange, brown, red bands: digits 1 0 0, multiplier x1000, tolerance 1 percent and a red sixth band meaning 50 ppm per kelvin temperature coefficient — Figure 5. A 6 band 100 kΩ resistor. The red sixth band is the temperature coefficient, 50 ppm/K. Open this resistor in the simulator.

Common resistor values and their colours

These are the values that fill most parts drawers. Learn the first two bands of the E12 series and you can recognise almost any 5% resistor at a glance.

Value	4 band (±5%)	5 band (±1%)	Typical use
10 Ω	brown black black gold	brown black black gold brown	current sense, gate resistor
100 Ω	brown black brown gold	brown black black black brown	series protection
220 Ω	red red brown gold	red red black black brown	LED on 5 V
330 Ω	orange orange brown gold	orange orange black black brown	LED, dimmer
470 Ω	yellow violet brown gold	yellow violet black black brown	LED on 12 V
1 kΩ	brown black red gold	brown black black brown brown	transistor base
2.2 kΩ	red red red gold	red red black brown brown	I2C pull-up
4.7 kΩ	yellow violet red gold	yellow violet black brown brown	pull-up, I2C
10 kΩ	brown black orange gold	brown black black red brown	pull-up, divider
47 kΩ	yellow violet orange gold	yellow violet black red brown	divider, bias
100 kΩ	brown black yellow gold	brown black black orange brown	high impedance divider
1 MΩ	brown black green gold	brown black black yellow brown	bleed resistor

Why these values and not round numbers like 500 Ω? The E12 series (10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82) is spaced so that each value is about 21% above the last, the step that lets ±10% tolerance ranges just touch. E24 halves the step for 5% parts and E96 does the same for 1%. So if you decode a resistor as 5 kΩ, stop: 5 kΩ is in none of the series. The nearest E24 value is 5.1 kΩ (green, brown, red), and you have probably misread a band. Our guides to pull-up resistor values and LED resistors on Arduino show where the common values come from.

What about gold and silver in the middle?

Gold and silver do two jobs. In the last position they are tolerances: gold ±5%, silver ±10%. In the multiplier position they divide: gold ×0.1, silver ×0.01. That is how values under 10 Ω are marked. Yellow, violet, gold, gold is 47 × 0.1 = 4.7 Ω ±5%, and yellow, violet, silver, gold is 0.47 Ω, a typical current sense resistor in a power supply. Position tells you which job a gold band is doing.

Common mistakes when reading resistors

Reading the multiplier as a digit. Red, red, red is 2.2 kΩ, not 222 Ω.
Confusing red, orange and brown. Under warm light and on old or heat-browned parts they look alike. A 1 kΩ (brown, black, red) and a 10 kΩ (brown, black, orange) differ only in that band. Measure before you solder.
Trusting the body colour. Blue bodies often mean 1% metal film and beige 5% carbon film, but it is a convention, not part of the code.
Using colours on SMD parts. Surface mount resistors use printed numbers instead: 103 is 10 × 10³ = 10 kΩ, and 4R7 is 4.7 Ω.

Try it yourself

Open the 220 Ω resistor in the simulator and tap its third band to step brown, red, orange. Watch the value jump from 220 Ω to 2.2 kΩ to 22 kΩ while the digits stay the same. Then switch to 5 bands and see the same value re-coded with an extra digit, or open the colour chart view to print the table. For the LED resistor you are about to pick, the LED resistor calculator works out the value and why LEDs need a resistor explains the reason.

Printable portrait resistor color code chart with the digit, multiplier, tolerance and temperature coefficient for every band colour, plus example 4.7 kilohm 4 band and 1 kilohm 5 band resistors — Figure 6. A portrait version of the chart sized for a phone screen or a printout. Open the chart in the simulator.

Sources

Wikipedia, "Electronic color code", resistor table per IEC 60062:2016 (digits, multipliers, tolerance letters, temperature coefficients, and the 2016 changes to grey, orange and yellow tolerances): en.wikipedia.org/wiki/Electronic_color_code
Vishay, "Marking of resistors" document 20020 (six band code and the sixth band temperature coefficient colours: brown 100, red 50, yellow 25, orange 15, blue 10, violet 5 ppm/K): vishay.com/docs/20020/smdresistormarking.pdf

Frequently asked questions

What is the easiest way to remember the resistor color code?

Learn it as a rainbow with two colours on each end. Black 0 and brown 1 come first, then the rainbow red, orange, yellow, green, blue, violet for 2 to 7, then grey 8 and white 9. The phrase B B ROY of Great Britain has a Very Good Wife spells the order.

What is the color code of a 10k ohm resistor?

Brown, black, orange, gold on a 4 band resistor: 1, 0, three zeros, plus or minus 5 percent. On a 5 band 1 percent resistor it is brown, black, black, red, brown.

How do I know which end of a resistor to read from?

Start at the end where the bands are bunched together. The tolerance band, usually gold, silver or brown, sits a little apart at the other end. Gold and silver are never the first band, and usually only one reading direction gives a standard value.

What does the third band on a resistor mean?

On a 4 band resistor the third band is the multiplier, the number of zeros after the first two digits. Red means two zeros, so red red red is 2,200 ohms. On a 5 or 6 band resistor the third band is a third digit and the fourth band is the multiplier.

What does a gold band on a resistor mean?

In the last position gold means plus or minus 5 percent tolerance. In the multiplier position it means times 0.1, so yellow violet gold gold is 4.7 ohms with 5 percent tolerance.