Science / Electronics
Resistor Colour Code Calculator
Read 4-, 5-, and 6-band resistor colour codes into ohms, tolerance, and temperature coefficient, or find the colours for a value, with the nearest E12, E24, and E96 standard values.
Resistor Colour Code Calculator: The colours follow IEC 60062. On a 4-band resistor the first two bands are digits, the third a power of ten, and the fourth the tolerance; 5- and 6-band resistors have three digits, and the sixth band is the temperature coefficient in parts per million per kelvin. For a value you type, the tool rounds it to the significant digits the bands can show and finds the nearest values in the E12, E24, and E96 series that resistors are sold in. Runs 100% locally in your browser with zero server file uploads.
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4.7 kΩ ±5%
Between 4.465 kΩ and 4.935 kΩ
Colours for a value
YellowVioletRed+ tolerance band
Nearest standard values: E12 4.7 kΩ · E24 4.7 kΩ · E96 4.75 kΩ
Telling the colours apart
Brown, red, and orange can look alike under warm light, and so can blue, violet, and grey. Read resistors under daylight or a white LED, and when in doubt check with a multimeter, which settles it in seconds.
Surface-mount resistors are printed with digits instead of colours: 472 means 47 followed by two zeros, 4.7 kΩ, the same rule as the colour bands.
Choosing a resistor
Work out the value you need, then pick the nearest standard value; for an LED, a slightly higher resistance than calculated is the safe side. Check the power rating too: the power a resistor must handle is the current squared times the resistance, and common through-hole resistors are rated at 0.25 W.
How to use it
- Choose 4, 5, or 6 bands and pick each band's colour, starting from the end without the gold or silver band.
- Read the resistance, tolerance, and the range it can be in.
- Or type a value, such as 4.7k, to see its colours and the nearest standard values.
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Frequently asked questions
Which way do I read a resistor?
Start from the end with the bands closer together, and read towards the gold or silver tolerance band, which is often a little apart from the others. A band of gold or silver can only be a multiplier or a tolerance, never the first digit.
What colour is a 10k resistor?
Brown, black, orange, then the tolerance band, such as gold for ±5%: 1, 0, and three zeros. On a 5-band resistor it is brown, black, black, red, then tolerance, such as brown for ±1%.
What does tolerance mean?
How far the real resistance may be from the marked value: a 1 kΩ resistor with ±5% tolerance is between 950 Ω and 1,050 Ω. Gold is ±5%, silver ±10%, brown ±1%, and red ±2%.
What are E12 and E24?
Standard series of preferred values, with 12 or 24 values in each decade spaced evenly on a logarithmic scale, such as 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, and 82 for E12. Precise resistors use the E96 series.
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