# Resistor Color Code Calculator

Created by Hanna Pamuła, PhD
Reviewed by Dominik Czernia, PhD and Steven Wooding
Last updated: Jan 18, 2024

With this resistor color code calculator, you'll quickly and easily find out the resistance of your resistor component. Just choose how many bands your resistor has – 4, 5, or 6, select the colors, and in the blink of an eye, you'll get the resistance with tolerance, range, and temperature coefficient value (if you've chosen 6 band resistor color code).

If you want to understand how to read resistor color code, scroll down, and you'll find their formulas and explanation. Also, we show a 10k resistor color code as well as many other informative examples.

## How to read resistor color code?

Color bands are an easy and cheap way of indicating the value of an electronic component. The printed alphanumeric codes would be too small to read on the tiniest resistors, so the color code was developed in the early 1920s.

The first question which usually arises is: how do I know from which end I should start reading my resistor color code?
Fortunately, a couple of visual hints exist!

• In a usual case, the bands are not spaced regularly – there's a gap, and bands are somehow grouped. The larger gap occurs before the tolerance band. Put the bigger group on the left side and read resistors from left to right.

• Very often, the tolerance of the resistor is equal to 5% or 10%. These values are marked with metallic colors – gold and silver, respectively. However, the resistor color code never starts from such color – so if you find the metallic color on your resistor, it's definitely the tolerance value, so it must be placed on the right side. Again, read the resistor from left to right.

• Usually, the first band will be closest to the end (but not always, so then use other clues).

If none of the above appear to help your problem, you can always use a multimeter to tell between two possible resistances – and reading directions.

OK, let's get down to brass tacks: How to read resistor color code?

The value of the resistance is marked with the colors. Every color is a different number:

Color name

Digit

Color

Color name

Digit

Color

Black

$0$

Green

$5$

Brown

$1$

Blue

$6$

Red

$2$

Violet

$7$

Orange

$3$

Gray

$8$

Yellow

$4$

White

$9$

It's the color code working for the first 2 or 3 bands from the left side.

Then, we have the band called the multiplier, and the color meaning is different:

Color name

Multiply

Color

Color name

Multiply

Color

Black

$\times1\ \mathrm{Ω}$

Blue

$\times1\ \mathrm{MΩ}$

Brown

$\times10\ \mathrm{Ω}$

Violet

$\times10\ \mathrm{MΩ}$

Red

$\times100\ \mathrm{Ω}$

Gray

$\times100\ \mathrm{MΩ}$

Orange

$\times1\ \mathrm{kΩ}$

White

$\times1\ \mathrm{GΩ}$

Yellow

$\times10\ \mathrm{kΩ}$

Gold

$\times0.1\ \mathrm{Ω}$

Green

$\times100\ \mathrm{kΩ}$

Silver

$\times0.01\ \mathrm{Ω}$

Here, color represents the power of 10, by which the number created from previous bands must be multiplied. You can express the multipliers with prefixes like kilo, mega, or giga ($\mathrm{kΩ}$, $\mathrm{MΩ}$, $\mathrm{GΩ}$), but also the scientific notation is used – e.g., $10^9\ \mathrm{Ω}$ (gigaohm).

And finally, the last band, which occurs in all types of resistors – 4, 5, and 6 band – is a tolerance band. It's expressed in percentages, and the variation in components resistance is mostly of a statistical nature (normal distribution):

Color name

Tolerance

Color

Color name

Tolerance

Color

Brown

$\pm1\%$

Violet

$\pm0.1\%$

Red

$\pm2\%$

Gray

$\pm0.05\%$

Green

$\pm0.5\%$

Gold

$\pm5\%$

Blue

$\pm0.25\%$

Silver

$\pm10\%$

So that's all you need to know about the color meaning for 4 and 5-band resistor color codes. For 6-band resistors, there's an additional ring indicating the temperature coefficient – read more about it in a paragraph dedicated to 6-band resistors. Scroll down and find out the formulas, depending on the type of your resistor!

## Example of how to use this resistor color code calculator

We've tried really hard to make the resistor color code calculator as simple and intuitive as possible, but if you have any problems, just have a look at the example below!

1. Choose the number of bands on your resistor. There are three options: 4, 5, or 6 bands. Let's assume you have a resistor with five bands.

2. Pick the colors of the bands. If you don't know which is the first and which is the last band, have a look at the pictures built into the calculator. Generally, there's a gap before the tolerance band, so that's how you can recognize the start and end. In our example, let's say we have the colors: brown, red, violet, black and red.

1. The calculator draws the colored bands. Compare them with your resistor. Are they in the same order?

2. When you finish entering all bands, the resistor color code calculator will show you the resistance, with tolerance and maximum and minimum value resulting from a tolerance. In our example, the resistance should be equal to $127\ \mathrm{Ω}$. Additionally, if you've entered a 6-band resistor color code, the 6th band meaning will also be displayed: the temperature coefficient, in $\small\mathrm{ppm/\degree C}$.

We also have other tools which are closely linked to the topic, like the wire resistance calculator or LED resistor calculator, to determine what resistance you should use when creating an electronic circuit with LEDs. You can also check out our Wheatstone bridge calculator.

## 4-band resistor color code

The formula for 4 band resistor color code may be written as:

$\scriptsize \!R\!=\!\mathrm{band}_3\!\!\times\!\!((10\!\times\!\mathrm{band}_1)\!+\!\mathrm{band}_2)\!\pm\!\mathrm{band}_4$

But what does it mean, and how to read that? Let's have a look at the example, and everything should be clear:

1. Assume we have a resistor with 4 color bands. The colors are green, red, red, and gold.
1. Take the first two colors – green and red. The corresponding digits are 5 and 2. Put them together, and you'll get the number 52. You can write it formally as:
\scriptsize\qquad \begin{align*} (10&\!\times\!\mathrm{band}_1)\!+\!\mathrm{band}_2\\ (10&\!\times\!5)\!+\!2=52 \end{align*}
1. Take the third band – red. This time the meaning is different because it's the multiplier band, and the corresponding factor is $100\ \mathrm{Ω}$. Multiply the previous result by this value.
\scriptsize \qquad \begin{align*}R\!&=\!\mathrm{band}_3\!\times\!((10\!\times\!\mathrm{band}_1)\!+\!\mathrm{band}_2)\\ \!&=\!100\ \mathrm{Ω}\!\times\!((10\!\times\! 5)\!+\!2)=5.2\ \mathrm{kΩ} \end{align*}

Here you go! That's your resistor value. But one band is left. And it's…

1. The tolerance band. In our case, the band is gold, so the tolerance is equal to $5\%$. That means that our resistor value is not exactly the $5.2\ \mathrm{kΩ}$, but $5.2\ \mathrm{kΩ} \pm 5\%$. So the value may lay anywhere in the range $\langle R_{\mathrm{min}}, R_\mathrm{max}\rangle$:

Minimum value: $R_{\mathrm{min}} = R - (\mathrm{band}_4 \times R)$ in our example:

\scriptsize \qquad \begin{align*} R_{\mathrm{min}}&=5.2\ \mathrm{kΩ}-(5.2\ \mathrm{kΩ}\times 5\%)\\ &=5.2\ \mathrm{kΩ}-0.26\ \mathrm{kΩ}=4.94\ \mathrm{kΩ} \end{align*}

Maximum value: $R_{\mathrm{max}} = R +( \mathrm{band}_4 \times R)$ so in our case:

\scriptsize \qquad \begin{align*} R_{\mathrm{max}}&=5.2\ \mathrm{kΩ}+(5.2\ \mathrm{kΩ}\times 5\%)\\ &=5.2\ \mathrm{kΩ}+0.26\ \mathrm{kΩ}=5.46\ \mathrm{kΩ} \end{align*}

And that's all! It wasn't so hard, was it? Check out the result with our resistor color code calculator.

## 5-band resistor color code

The difference between 4 and 5-band resistors lies in significant digits. The number of sig-figs is 2 or 3, respectively. So we may write the formula for 5 band resistor color code as:

\scriptsize \begin{align*} R\!&=\!\mathrm{band}_4\!\times\!((100\!\times\!\mathrm{band}_1)\!+\!(10\!\times\!\mathrm{band}_2)\\ &\quad\!+\!\mathrm{band}_3)\pm\mathrm{band}_5 \end{align*}

Let's just expand our previous example - after two significant bands, green and red, let's put the blue one:

1. For green, red, and blue, the corresponding digits are 5, 2, and 6. It's our number – $526$. Write it formally as:
\scriptsize \qquad\! \begin{align*} &(100\times\mathrm{band}_1)+(10\times\mathrm{band}_2)+\mathrm{band}_3\\ &(100\times5)+(10\times2)+6=526 \end{align*}
1. The fourth red band is our multiplier ring again, with the corresponding factor of 100 Ω. Multiply the obtained result by this value:
\scriptsize\quad\ \ \begin{align*} R\!&=\!\mathrm{band}_4 \!\times\!((100\!\times\!\mathrm{band}_1)\!+\!(10\!\times\!\mathrm{band}_2)\!\\ \!&\quad+\!\mathrm{band}_3) \end{align*}

Hence:

\scriptsize\qquad \begin{align*} R\!&=\!100\!\times\!((100\!\times\!5)\!+\!(10\!\times\!2)\!+\!6)\\ \!&=52,\!600\ \mathrm{Ω}=52.6\ \mathrm{kΩ} \end{align*}
1. And finally, the gold tolerance band means tolerance of $5\%$. Our resistor may lay anywhere in the range $\langle R_{\mathrm{min}}, R_\mathrm{max}\rangle$:

Minimum value: $R_{\mathrm{min}} = R - (\mathrm{band}_5 \times R)$ so in our example:

\scriptsize \qquad \begin{align*} R_{\mathrm{min}}&=52.6\ \mathrm{kΩ}-(5.26\ \mathrm{kΩ}\times 5\%)\\ &=52.6\ \mathrm{kΩ}-2.63\ \mathrm{kΩ}=49.97\ \mathrm{kΩ} \end{align*}

Maximum value: $R_{\mathrm{max}} = R + (\mathrm{band}_5 \times R)$ in our case:

\scriptsize \qquad \begin{align*} R_{\mathrm{max}}&=52.6\ \mathrm{kΩ}+(5.26\ \mathrm{kΩ}\times 5\%)\\ &=52.6\ \mathrm{kΩ}+2.63\ \mathrm{kΩ}=55.23\ \mathrm{kΩ} \end{align*}

## 6-band resistor color code

A 6 band resistor color code is almost like 5 band resistor, but it additionally includes a temperature coefficient band at the last position. This thermal coefficient (TCR) defines the change in resistance as a function of the ambient temperature, and it's expressed in $\mathrm{ppm/\degree C}$.

For example, suppose we have a resistor with TCR equal to $50\ \mathrm{ppm/\degree C}$. In that case, it means that the resistance won't change more than $0.00005$ ohms per ohm per degree Centigrade temperature change (but only in referenced temperature range, check out the element's manual). Given TCR and information that the resistor's initial value at room temperature $T_0 = 25\ \mathrm{\degree C}$ is equal to, e.g., $R_0 = 50\ \mathrm{Ω}$, we can calculate the resistance $R$ after heating or cooling element to another temperature, e.g., $T = 50\ \mathrm{\degree C}$:

\scriptsize \begin{align*} R &= R_0\times(1+\mathrm{TCR}\times(T-T_0))\\ &=50\ \mathrm{Ω} \times (1+0.00005\ \frac{1}{\degree\mathrm{C}}\times25\ \degree\mathrm{C} )\\ &=50.0625\ \mathrm{Ω} \end{align*}

For those calculations, we can also use kelvin instead of degree Centigrade temperature, as the difference between temperatures is the thing that matters, not the absolute temperature value.

A similar concept to TCR is a thermal expansion coefficient – here, not the resistance, but the length or volume of the element changes with the temperature.

Watch out! Sometimes, the sixth band doesn't mean the thermal coefficient but the reliability of the resistor, but those are sporadic cases.

The colors of the last band are coded as:

Color name

TCR [$\boldsymbol{\mathrm{ppm/\degree C}}$]

Color

Brown

$100$

Red

$50$

Yellow

$25$

Orange

$15$

Blue

$10$

Violet

$5$

## What's the 10k resistor color code?

There are many options, depending on the tolerance and number of bands.

• 4 band resistor color code for 10k resistor

Always first three bands are the same:

1. The first band is brown, as it stands for 1.
2. The second band is black, which means 0.
3. The third band – multiplier x $1\ \mathrm{kΩ}$ – is orange.
4. The fourth band depends on the tolerance – so any color is possible for the tolerance band.

Just to quickly check the calculations:

\scriptsize \begin{align*} R&=((10\times\mathrm{band}_1)+\mathrm{band}_2)\times\mathrm{band}_3\\ &=((10\times1)+0)\times 1\ \mathrm{kΩ}=10\ \mathrm{kΩ} \end{align*}

Yes! Looks good.

• 5 and 6 band resistor color code for 10k resistor

Always first four bands are fixed:

1. The first band is brown, as it stands for 1.
2. The second band is black, which means 0.
3. The third band is black, which means 0.
4. The fourth band is a multiplier x $100\ \mathrm{Ω}$ which is red.
5. The fifth (and sixth) band may be different, as they're the tolerance and thermal coefficient values.

Check out again:

\scriptsize \begin{align*} R&=((100\times\mathrm{band}_1)+(10\times\mathrm{band}_2)\\ &\quad+\mathrm{band}_3)\times\mathrm{band}_4\\ &=((100\times1)+(10\times0)+0)\times 100\ \mathrm{Ω}\\ &=100\times 100\ \mathrm{Ω}=10\ \mathrm{kΩ} \end{align*}

It's working. Great!

🙋 Now that you know how to read your resistor, you can use this skill to design the best circuits for your needs. Omni has a great collection of tools to help you do so. Try the:

## FAQ

### How should I read color-coded resistors?

Here's a guide on how to read color-coded 4- or 5-band resistors:

1. Find the reading direction: there should be an increased space between the last two bands.
2. Look at the first two (4-band) or three (5-band) bands and assign their color to the numbers.
3. Check the color of the multiplier band, indicating the value by which the digits are multiplied.
4. Assign the color of the tolerance band to the value.

### Which side should I read a resistor color code?

Start reading where the colored bands are grouped closer together. Hold the resistor with these grouped bands to the left. You should notice a space between them, and the last band (or the last two in a 6-band type). Resistors should always be read from left to right.

### What will be the resistance of the 5-band resistor?

1kΩ ± 5%, if we assume that its color code is brown-black-black-brown-gold. To find this:

1. Assign numbers to the colors of the first three bands: it's 100.
2. Find the multiplier for the fourth, brown band: it will be 10.
3. Multiply 100 by 10.
4. The gold indicates a 5% margin of error, so the resistance will be between 950 Ω and 1050 Ω.

### What's the color code for 4-band 220 Ohm resistor?

The color code is red-red-brown-gold. The first significant number is 2, and the value 2 corresponds to the color red. The second significant number is also 2, so it also gives us red. The multiplier is 10 (22 × 10 = 220 Ω), so the third band will be brown. We can accept resistance with a 5% margin of error, so the last band is gold.

### What is a reliability band on a resistor?

The reliability band determines the failure rate (%) per 1,000 hours of work. You may encounter this additional band on military specified resistors. However, such a solution is rarely used in commercial electronics.

Hanna Pamuła, PhD
Number of bands
Four
Bands colors
Band 1
Select...
Band 2
Select...
Multiplier
Select...
Tolerance
Select...
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