Resistor Color Code Calculator

Each color band on a resistor represents a digit, multiplier, or tolerance. For a 4-band resistor, the first two bands are digits, the third is the multiplier, and the fourth is tolerance. For 5- and 6-band resistors, there are three digit bands before the multiplier. Read the bands from left to right, starting from the band closest to one end of the resistor.

4-band resistors use two significant digits, a multiplier, and a tolerance band — suitable for general-purpose use. 5-band resistors add a third significant digit for greater precision. 6-band resistors include all of the above plus a temperature coefficient (tempco) band, indicating how resistance changes with temperature.

The tolerance band tells you how much the actual resistance may deviate from the stated value. For example, a 1 kΩ resistor with ±5% tolerance could measure anywhere between 950 Ω and 1,050 Ω. Tighter tolerances (like ±1%) are used in precision circuits, while ±5% or ±10% are common in general applications.

When gold or silver appears as the last or second-to-last band, it indicates tolerance — gold means ±5% and silver means ±10%. When gold or silver appear as the multiplier band, they represent fractional multipliers: gold is ×0.1 and silver is ×0.01, used for resistors below 10 Ω.

The temperature coefficient indicates how much the resistance changes per degree Celsius, measured in ppm/°C (parts per million per degree Celsius). A lower tempco means the resistor is more stable across temperature changes. This is important in precision analog circuits where temperature stability is critical.

Typically, the first band is the one closest to a lead or end of the resistor body. If one band is clearly spaced apart from the others, that is usually the tolerance band and should be read last. Gold and silver bands are never used as the first (digit) band, so if you see one of those, it must be the tolerance band on the far end.

This calculator covers all standard axial lead resistors using the IEC color code system, including 3-digit (4-band) and 4-digit (5- and 6-band) configurations. It supports multipliers from ×0.01 Ω up to ×1 GΩ. Surface mount (SMD) resistors use a numeric code rather than color bands and are not covered by this tool.

The IEC 60062 standard defines the color code system used worldwide for resistors and other passive components. The same color-to-digit mapping applies globally: black=0, brown=1, red=2, orange=3, yellow=4, green=5, blue=6, violet=7, grey=8, white=9. This standard has been in use since the early days of electronic component manufacturing.