Resistor Color Code Calculator
Find out the resistance value with this resistor color code calculator! Just choose the resistor type, select the colors, and the tool will display the resistance, tolerance, and range on the spot.
The formula
value = (digits) × multiplier, ± tolerance
Reading it the right way round
The bands encode significant digits, then a decimal multiplier, then a tolerance. Four-band resistors give two digits, five-band give three for tighter tolerances. Black through white run 0 to 9 in the digit positions, and the same colours serve as powers of ten in the multiplier position.
The most common mistake is reading from the wrong end. The tolerance band is usually gold or silver — neither of which is a digit colour — and is often separated by a slightly wider gap. If a reading gives an implausible value, reversing it usually gives a sensible one.
Gold and silver also serve as fractional multipliers, ×0.1 and ×0.01, which is how sub-ohm resistors are marked. That is the one case where gold in the multiplier position is a value rather than a tolerance.
Manufactured values follow the E-series: twelve per decade for ±10% parts, twenty-four for ±5%, ninety-six for ±1%. The steps are chosen so that consecutive values overlap within tolerance, which means a computed resistance that is not near an E-series value is usually a misread band.