Resistor Calculator

Decode a 4-band resistor color code into its resistance value and tolerance.

Resistance
1 kΩ ± 20%
TOLERANCE RANGE
Minimum
800 Ω
Nominal
1 kΩ
Maximum
1.2 kΩ
Equation used
Resistance = (10 × Digit_1 + Digit_2) × Multiplier, ± Tolerance%

Frequently Asked Questions

What do the first two color bands represent?

Bands 1 and 2 are the two significant digits of the resistance value — for example Brown-Black reads as digits 1 and 0, giving "10" before the multiplier is applied.

What does the third band (multiplier) do?

It scales the two-digit number by a power of 10 matching that color (e.g. Red = ×100), or by ×0.1 for Gold or ×0.01 for Silver when the resistance is very small — this is what turns "10" into, say, 10 kΩ or 1 Ω depending on the color chosen.

What does the tolerance band and the Min/Max range mean?

The 4th band gives the manufacturer's guaranteed accuracy — e.g. a Gold band means ±5%. The Minimum and Maximum values show the real-world range the resistor's actual resistance should fall within, given that tolerance.