About the Resistor Color Code Calculator
This calculator works both ways. In Colours to value mode, pick the colour of each band of a 4, 5 or 6 band resistor, and it shows the resistance, the tolerance, the range the real value may fall in and, for six bands, the temperature coefficient. A drawing of the resistor changes colour as you choose. In Value to colours mode, type a resistance and it shows the bands to look for, and suggests the nearest standard E24 value when yours is not one. Colours can fade or look alike, especially brown, red and orange, and the reading direction matters, so measure with a multimeter when in doubt. The colour code says nothing about the power rating of the part.
Updated October 2026
How to use the Resistor Color Code Calculator
- 1Choose 4, 5 or 6 bands.
- 2In Colours to value mode, pick the colour of each band from the menus, starting from the end where the bands are closest together.
- 3Read the resistance, tolerance and range next to the drawing.
- 4Or switch to Value to colours, type the resistance and pick the tolerance.
- 5Follow the list of colours, or tap Use it to switch to the nearest standard value.
Reading the colour bands
Each colour stands for a digit: black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8 and white 9. On a 4-band resistor, the first two bands give the number, the third tells how many zeros to add, and the fourth gives the tolerance.
For example, yellow, violet, orange and silver is 4, 7 and three zeros, or 47,000 Ω, which is 47 kΩ, with a tolerance of ±10 percent.
4, 5 and 6 bands
- 4 bands: two digits, multiplier, tolerance. Common on general-purpose parts.
- 5 bands: three digits, multiplier, tolerance. Used where the value needs more accuracy.
- 6 bands: the same as 5 bands plus a temperature coefficient.
- Value to colours mode uses two digits for 4 bands and three digits for 5 or 6 bands, and tells you when it had to round.
Standard values and tolerance
A resistor marked 1 kΩ ±5 percent is not exactly 1,000 Ω. It may be anywhere from 950 to 1,050 Ω, and the calculator shows this range. Circuits are designed so this spread does not matter, or a tighter tolerance is chosen.
The standard E24 series is built for 5 percent parts, and closer series, such as E96, exist for 1 percent parts. When you compute a value with the Ohm's Law Calculator, choose the nearest standard value, checking the power rating as well.
Checking with a multimeter
Bands fade, colours are hard to tell apart under warm light, and some makers use slightly different shades. If the reading does not match what you expect, take the resistor out of the circuit and measure it with a multimeter on its ohms range.
Measured in a circuit, the reading can be wrong because other parts create parallel paths. A power rating such as a quarter watt is printed on the packaging or judged from the size of the part; it is not part of the colour code. To check a colour band by sight, compare it in the Color Converter, and change number bases with the Number Base Converter if your project needs it.
Features
- 4, 5 and 6 band resistors
- Colour swatches and a drawing that updates
- Tolerance range in ohms
- Temperature coefficient for 6 bands
- Colours for any value, with the nearest E24 standard value
- Values from 0.01 Ω to gigaohms
- Runs in your browser
Frequently asked questions
How do I read a 4-band resistor?
The first two bands are digits, the third is the multiplier and the fourth is the tolerance. Brown, black, red, gold reads 1, 0, times 100, ±5 percent: 1,000 Ω, or 1 kΩ. Choose 4 bands and pick those colours to see it.
What do gold and silver bands mean?
As the tolerance band, gold means ±5 percent and silver ±10 percent. As the multiplier, gold means times 0.1 and silver times 0.01, used for resistors under 10 Ω. Neither can be a digit.
How do I read a 5-band resistor?
Five bands give three digits, a multiplier and a tolerance. Brown, black, black, red, brown reads 1, 0, 0, times 100, ±1 percent, which is 10 kΩ. These precision parts often have tolerances of 1 percent or better.
Which end do I start reading from?
Start at the end where the bands are closest together. The tolerance band is usually set a little apart from the rest and is often gold or silver, which cannot start a valid reading. If both ends look alike, measure the part with a multimeter.
What is the temperature coefficient band?
The sixth band tells how much the resistance drifts with temperature, in parts per million per degree. Brown is 100 ppm/K, red 50, and blue 10. Low numbers mean a more stable part, which matters in measuring circuits.
What are E24 standard values?
Resistors are made in a fixed series of values so that each step is about 10 percent from the next. E24 has 24 steps per decade, such as 10, 11, 12, 13, 15 and 16. If your calculated value is not in the series, use the nearest one, and the page will name it for you.