Resistor color code calculator

How to read the bands

Hold the resistor with the tolerance band - usually gold or silver, and often a little apart from the others - on the right. Read from the left:

• 4-band: two digits, a multiplier, then tolerance. Yellow-violet-red-gold is 4, 7 × 100 = 4,700 Ω (4.7 kΩ) ±5%.
• 5-band: three digits, a multiplier, then tolerance - used for 1% and better resistors. Brown-black-black-red-brown is 100 × 100 = 10 kΩ ±1%.
• 3-band: two digits and a multiplier, no tolerance band - that means ±20%.

Six-band resistors add a temperature coefficient band at the end; read the first five as a 5-band resistor.

The colors

Black 0, brown 1, red 2, orange 3, yellow 4, green 5, blue 6, violet 7, grey 8, white 9. As a multiplier the color is the number of zeros (red = ×100), with gold ×0.1 and silver ×0.01 for values under 10 Ω.

When the bands are burnt

A resistor that's overheated often has discoloured bands - brown, red and orange are easy to confuse, and blue and violet can look alike. Measure it out of circuit if you can, check the board's other copies of the same part, or look for the same board in our board library, where many resistors are marked with their values. Replacement resistors are in the parts catalogue.

Questions

Which end do I start reading from?

The end without the gold or silver tolerance band - the bands are usually bunched closer to that end. If there's no gold or silver, the wider-spaced band is the tolerance band.

What does a gold or silver band mean?

At the end it's the tolerance: gold ±5%, silver ±10%. In the multiplier position, gold means ×0.1 and silver ×0.01, for values below 10 Ω.

Can I find the colors from a value?

Yes - type the value (for example 4.7k) in the box under the calculator and press Show colors.