Resistor Color Code Calculator — 4 and 5 band
Decode resistor color bands to a value, or convert a value back to bands. Supports 3, 4, 5 and 6-band resistors.
Example: Yellow, Violet, Red, Gold is 4.7 kΩ ±5% (4.465 kΩ to 4.935 kΩ).
Formula
R = (digits as a whole number) × multiplierCalculations follow IEC 60062.
Worked example
Yellow, Violet, Red, Gold is 4.7 kΩ ±5% (4.465 kΩ to 4.935 kΩ).
digits = band colours in order
Yellow = 4, Violet = 7
47
R = digits × multiplier
R = 47 × 100 (Red)
R = 4.7 kΩ
range = R ± tolerance
4.7 kΩ ± 5%
4.465 kΩ … 4.935 kΩ
Any part within this window is in spec.
Frequently asked questions
How do I read a 4-band resistor?
The first two bands are digits, the third is a power-of-ten multiplier, and the fourth is tolerance. Yellow-violet-red-gold is 4, 7, ×100, ±5% — a 4.7 kΩ resistor. Hold the resistor with the tolerance band (usually gold or silver, and set slightly apart) on the right.
Which end do I start reading from?
Start at the end where the bands are bunched together. The tolerance band sits alone at the other end, and gold or silver is always a tolerance or multiplier band — never a digit — so if you see one of those first, you are reading the resistor backwards.
What is the difference between 4-band and 5-band resistors?
A 5-band resistor carries three significant digits instead of two, so it can express tighter values like 4.99 kΩ. They are typically 1% parts drawn from the E96 series, whereas 4-band parts are usually 5% E24.
What do gold and silver bands mean?
In the multiplier position they divide rather than multiply: gold is ×0.1 and silver is ×0.01, which is how sub-10 Ω values are printed. In the tolerance position gold is ±5% and silver is ±10%.
Why does my measured resistance differ from the colour code?
Tolerance. A 4.7 kΩ ±5% resistor is in spec anywhere from 4.465 kΩ to 4.935 kΩ. Measuring a resistor while it is still soldered into a circuit will also read low, because parallel paths in the board are being measured too.
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