Utility
Resistor Colour Code Calculator
Read the bands on a resistor to IEC 60062, in either direction, and check the value against the E-series so a misread shows up as one. Three to six bands, and a reverse lookup from a value back to its colours.
The bands
What it reads
1 kΩ
±5% (J)
- Actual value lies between
- 950 Ω – 1.05 kΩ
- Preferred series
- In E6, E12, E24, E48, E96
Read from the other end
Reversed, these bands do not form a legal value, so there is only one way to read this resistor.
The other way round
Enter a resistance and see the bands that carry it. Shown with a gold tolerance band; swap it for whichever tolerance you need.
Yellow · Violet · Red · Gold
How to use it
- Count the bands and pick that number above.
- Hold the resistor with the grouped bands to the left and the lone band to the right, and set each band's colour in order.
- Read the value, its tolerance, and the range the actual part is guaranteed to fall in.
- Check the preferred-series line. If it says none, you have probably misread a band or the resistor is the other way round.
- To go the other way, type a resistance at the foot of the page and the colours appear.
How it works
The first two or three bands are digits, the next is a power of ten to multiply them by, and the one after that is the tolerance. A sixth band, where present, is the temperature coefficient.
Gold and silver are the only colours that divide rather than multiply — ×0.1 and ×0.01 — which is how resistors below ten ohms are marked.
Tolerance bands carry IEC letters as well as percentages: F is ±1%, J is ±5%, K is ±10%, M is ±20%.
The E-series check compares your value against the ranges resistors are actually manufactured in, from E6 through E96.
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Common questions
Which end do I start reading from?
The end with the bands grouped closest together. The tolerance band is normally set slightly apart from the rest, and on a four-band resistor it is gold or silver, which are never digits — so if you see gold or silver at one end, that is the end you finish at. When both directions give a legal value, this tool says so rather than picking one for you.
Why does it say my value is not in any series?
Because resistors are manufactured to preferred values — the E-series — rather than to arbitrary numbers. E24 covers the 5% parts, E96 the 1% parts. If your reading lands on something like 4.5 kΩ, no one makes that: it is almost certainly a misread 4.7 kΩ, or the resistor read backwards. That check is the main reason to use this rather than a printed chart.
Some charts give orange and yellow a tolerance. Why doesn't this?
Because IEC 60062 does not. Orange and yellow carry digits and temperature coefficients; the tolerance colours are brown, red, green, blue, violet, grey, gold, silver, and a missing band. The ±0.05% and ±0.02% figures attached to orange and yellow circulate widely and are left out here deliberately.
What does the sixth band mean?
Temperature coefficient, in parts per million per kelvin — how much the resistance drifts as the part warms up. It is worth noting the order is not what you would guess: orange is 15 ppm/K and yellow is 25, so it does not simply climb with the colour sequence the way the multipliers do.
My resistor has only three bands.
Then it has no tolerance marking, which the standard reads as ±20%. That is the same as an explicit fourth band of no colour at all, and this tool treats them identically.