Every electronics project uses resistors, but they are far too small to print a value on. Instead, they use colored bands. Learning how to read resistor color codes takes only a few minutes, and after that you will never have to guess which resistor to use again.
This guide explains how to read resistor color codes step by step, with an easy memory trick, worked examples and a quick look at the tiny surface-mount resistors found on modern boards.
The Color Values You Need to Know
Each color stands for a number from 0 to 9. Learning these ten values is the first step in how to read resistor color codes, and the order never changes, so once you remember it, you can read any resistor:
| Color | Digit | Multiplier |
|---|---|---|
| Black | 0 | ×1 |
| Brown | 1 | ×10 |
| Red | 2 | ×100 |
| Orange | 3 | ×1,000 |
| Yellow | 4 | ×10,000 |
| Green | 5 | ×100,000 |
| Blue | 6 | ×1,000,000 |
| Violet | 7 | ×10,000,000 |
| Gray | 8 | — |
| White | 9 | — |
| Gold | — | ×0.1 |
| Silver | — | ×0.01 |
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How to Read Resistor Color Codes from Memory
The colors follow the rainbow, with black and brown at the start and gray and white at the end. A popular memory sentence, used by most people who learn how to read resistor color codes, takes the first letter of each color:
Big Boys Race Our Young Girls But Violet Generally Wins: black, brown, red, orange, yellow, green, blue, violet, gray, white.
Alternatively, think “black is zero because it has no light, and white is nine because it has all of it”. Either way, after a few practice resistors you will not need the trick anymore.
How to Read Resistor Color Codes on a 4-Band Resistor
Most resistors in starter kits have four bands, so this is where learning how to read resistor color codes really pays off. To read them, follow these steps:
- Hold the resistor so the gold or silver band is on the right.
- Read the first band: this is the first digit.
- Read the second band: this is the second digit.
- Read the third band: this is the multiplier, or how many zeros to add.
- Read the last band: this is the tolerance.
For example, yellow, violet, red and gold means 4, 7, ×100 and ±5%. So the value is 47 × 100 = 4,700 Ω, written as 4.7 kΩ.
How to Read Resistor Color Codes: Worked Examples
| Bands | Calculation | Value |
|---|---|---|
| Brown, black, red, gold | 1, 0, ×100 | 1 kΩ ±5% |
| Red, red, brown, gold | 2, 2, ×10 | 220 Ω ±5% |
| Brown, black, orange, gold | 1, 0, ×1,000 | 10 kΩ ±5% |
| Orange, orange, yellow, gold | 3, 3, ×10,000 | 330 kΩ ±5% |
| Yellow, violet, gold, gold | 4, 7, ×0.1 | 4.7 Ω ±5% |
To practice how to read resistor color codes, start with the 220 Ω resistor, the one you will use most often in beginner projects, for example to protect an LED in our first Arduino project.
How to Read a 5-Band Resistor
Precision resistors often have five bands, but how to read resistor color codes on them is almost the same. The only difference is that there are three digit bands instead of two, and the tolerance is usually tighter, typically brown for ±1%.
For instance, brown, black, black, red and brown means 1, 0, 0, ×100 and ±1%, which gives 100 × 100 = 10 kΩ ±1%. In other words, you simply read one extra digit before the multiplier.
Tolerance: Why Your Multimeter Shows a Different Value
The tolerance band tells you how much the real value can vary, which is the last part of how to read resistor color codes. A 1 kΩ resistor with a gold band (±5%) can measure anywhere from 950 Ω to 1,050 Ω and still be perfectly fine.
Therefore, do not worry if your multimeter shows 987 Ω instead of exactly 1,000 Ω. As long as it is within the tolerance range, the resistor is working correctly.
Reading Surface-Mount Resistor Codes
Surface-mount resistors are too small for bands, so knowing how to read resistor color codes will not help here. Instead, they use printed numbers:
- 3-digit codes: the first two digits are the value and the third is the number of zeros. For example, 103 = 10 followed by three zeros = 10 kΩ.
- 4-digit codes: the first three digits are the value and the last one is the number of zeros. For example, 1002 = 100 followed by two zeros = 10 kΩ.
- The letter R: it marks the decimal point. For example, 4R7 = 4.7 Ω.
Some precision surface-mount parts use a different system called EIA-96. You can find its full table in the electronic color code article on Wikipedia.
Check Your Answer in Seconds
Once you know how to read resistor color codes, it is still worth double-checking before you solder. Our free resistor color code calculator shows the value, the tolerance and the real range as soon as you pick the colors. It also works in reverse, so you can type 4.7k and see which bands to look for.
If you are still choosing a board for your next project, our comparison of Raspberry Pi vs Arduino will help you decide.
FAQ: How to Read Resistor Color Codes
Which side of a resistor do you read first?
Start from the side opposite the gold or silver band. The tolerance band is usually slightly apart from the others, and it is always read last.
What does a gold band mean on a resistor?
In the last position, gold means a tolerance of ±5%. In the multiplier position, gold means ×0.1, which is used for values below 10 ohms.
How do I read a resistor with no gold or silver band?
Look for the band that is set further apart or is wider; that is the tolerance band. A resistor with only three bands has no tolerance band and a tolerance of ±20%.