IT operations

Resistor Color Code Calculator

Decode 4-band resistor color codes to find the resistance value and tolerance. Use this Networking and IT tool to enter your numbers, review the result, and understand the key assumptions before making the next decision.

What you get
A focused calculator, clear explanation, common questions, and useful next tools.
Quick intro
Calculator
Result
Explanation
Common questions
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Calculator tool

How this calculator works
The result depends on the numbers you enter and the assumptions shown below.

Resistor color codes use colored bands to indicate resistance. Each color represents a digit (0–9). The third band is a multiplier and the fourth is tolerance. Formula: R = (d1×10 + d2) × 10^multiplier.

Review the inputs carefully and treat the output as an estimate. For decisions involving money, taxes, health, law, or security, compare the result with trusted professional guidance when needed.

Frequently asked questions

How do I read a 4-band resistor?

Hold the resistor with the tolerance band (usually gold or silver) on the right. Read left-to-right: digit, digit, multiplier, tolerance.