This resistor color code calculator converts the colour bands of a 4-band resistor into its resistance value and tolerance. Select the colour of each band to read the resistance instantly.
Resistor Color Code Calculator (4-band)
Formula
Resistance = (1st digit × 10 + 2nd digit) × multiplier, with the 4th band giving the tolerance.
How to Use This Calculator
- Select the colour of the first two digit bands.
- Select the multiplier band colour.
- Select the tolerance band, then click Calculate.
Worked Example
Brown, Black, Red, Gold = (1, 0) × 100 = 1000 Ω = 1 kΩ ±5%.
Frequently Asked Questions
How do you read a 4-band resistor?
The first two bands are digits, the third is the multiplier (power of ten) and the fourth is the tolerance.
What colour is the multiplier band for kilo-ohms?
An orange third band multiplies by 1000, giving kilo-ohm values.
What does a gold tolerance band mean?
A gold fourth band indicates a tolerance of plus or minus 5%.