Formula
This calculator uses the standard resistor color code calculator formula:
Frequently Asked Questions
For a 4-band resistor: bands 1 and 2 give the first two digits, band 3 is the multiplier, and band 4 is tolerance. For example, Brown-Black-Red-Gold = 1,000 Ω ±5%.
4-band resistors have two significant digits; 5-band resistors have three, providing higher precision. Most common resistors use 4 bands.
The gold or silver band (last band) indicates tolerance: gold = ±5%, silver = ±10%. If there is no band, tolerance is ±20%.
A 1 kΩ ±5% resistor has colour bands Brown-Black-Red-Gold (4-band) or Brown-Black-Black-Brown-Gold (5-band).
A 10 kΩ ±5% 4-band resistor is Brown-Black-Orange-Gold. The orange multiplier band represents ×1,000.
Resistors can fade or the colour ring spacing can be hard to read. Use a multimeter to measure actual resistance when in doubt.