Resistor Color Code Calculator
Select the four band colors on your resistor to find its resistance, tolerance, and the resulting value range.
How resistor color codes work
On a standard 4-band resistor, the first two bands are significant digits (0-9), the third band is a multiplier (a power of 10 to multiply the two digits by), and the fourth band is the tolerance — how far the actual resistance may vary from the stated value.
For example, brown-black-red-gold reads as 1, 0, ×100, giving (10) × 100 = 1,000 ohms (1 kΩ) with ±5% tolerance, so the actual resistance falls somewhere between 950 Ω and 1,050 Ω.
Frequently asked questions
What do the resistor color bands mean?
The first two bands give the significant digits of the value, the third band is a multiplier, and the fourth band indicates the tolerance (how precise the resistor is).
What does gold or silver mean on the tolerance band?
Gold means ±5% tolerance and silver means ±10% — the resistor's actual value can differ from the stated value by up to that percentage.
Can this calculator read 5-band or 6-band resistors?
This calculator covers the common 4-band code. 5- and 6-band resistors add an extra significant digit (and sometimes a temperature coefficient band) for higher precision, which isn't covered here.