Resistor Color Code Calculator
Read a resistor value from its colour bands, or find the bands for a value you need. Covers 4, 5 and 6 band resistors with tolerance, temperature coefficient and E series preferred values.
Last reviewed by the Radiatus Cloud team
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Value → bands
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Reading a resistor without a multimeter
The colour band system encodes a resistance, a tolerance and sometimes a temperature coefficient into three to six painted rings. It is the oldest surviving component marking convention in electronics and it is still on almost every through hole resistor, because printing digits on a two millimetre cylinder is impractical. Reading it is a small piece of arithmetic that is easy to get wrong under a desk lamp, particularly telling brown from red or violet from grey.
Which end do you start from
The classic mistake is reading the bands backwards. The tolerance band is usually gold or silver and sits slightly apart from the group, so the value bands are read from the opposite end. When there is no gold or silver band, look for the wider gap; on a five band resistor the gap sits before the tolerance ring. Reading a 4700 ohm resistor backwards gives 274 ohms, which is a very different circuit.
Preferred values tell you if you read it right
Resistors are manufactured in standardised series, so a five percent part comes from the E24 set and a one percent part from E96. If your reading produces a value that is not in the appropriate series, you almost certainly misread a band. This calculator flags whether the value you produced is a real preferred value, which catches the error before you solder the wrong part into the board.
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Frequently Asked Questions
How do I know which end to read from?
The tolerance band is usually gold or silver and separated by a wider gap. Put that band on the right. If every band is a colour, the wider gap sits between the multiplier and the tolerance ring.
What does a fifth band mean?
On a five band resistor the first three bands are significant digits and the fourth is the multiplier, giving a more precise value for one percent parts. On a six band resistor the sixth band is the temperature coefficient in parts per million per degree Celsius.
Why is my calculated value not a standard resistor?
Because a band was misread. Resistors come from the E12, E24, E96 or E192 preferred value series depending on tolerance. The calculator says whether your value appears in the appropriate series, which is a good check on the reading.
What do gold and silver mean as multipliers?
Gold multiplies by 0.1 and silver by 0.01, which is how sub ohm values are expressed. In the tolerance position gold means five percent and silver ten percent, so the position matters more than the colour.
Does the tolerance affect the circuit much?
It sets the range the actual part can be within. A 10k resistor at five percent is anywhere from 9500 to 10500 ohms. For dividers and timing that matters; for pull ups it rarely does. The tool shows the resulting minimum and maximum.
Privacy & Security
Everything runs in your browser; nothing is uploaded.
How to Use
Pick the band colours to read a resistance, or enter a resistance to see the bands.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.
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