Resistor Color Code
Decode 4-band resistor color codes.
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Introduction
Resistor Color Code — Decode 4-band resistor color codes. Enter Band 1, Band 2, Band 3 (multiplier), Band 4 (tolerance) to get an instant, accurate result.
Formula
4-band decode: value = (digit1×10 + digit2) × 10^(multiplier band), with tolerance read from the 4th band's color.
Step-by-step
- Enter the Band 1.
- Enter the Band 2.
- Enter the Band 3 (multiplier).
- Enter the Band 4 (tolerance).
- Click Calculate to see your result instantly.
Real-world example
Example: With Band 1 = brown, Band 2 = black, Band 3 (multiplier) = red, Band 4 (tolerance) = gold, the Resistor Color Code gives Ohms: 1000, Tolerance Pct: 5.
Frequently Asked Questions
What does the tolerance band tell me?
How much the actual resistance may vary from the labeled value — gold is ±5%, silver is ±10%.
Does this work for 5-band resistors?
No, this decodes standard 4-band resistors only.
What inputs does the Resistor Color Code need?
You'll need to provide: Band 1, Band 2, Band 3 (multiplier), Band 4 (tolerance). All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.
How accurate is the Resistor Color Code?
The Resistor Color Code applies the formula exactly as calculated — 4-band decode: value = (digit1×10 + digit2) × 10^(multiplier band), with tolerance read from the 4th band's color. — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.
Is the Resistor Color Code free to use?
Yes, the Resistor Color Code is completely free, requires no signup, and runs instantly in your browser.
About the Resistor Color Code
The Resistor Color Code uses a real, verifiable formula — 4-band decode: value = (digit1×10 + digit2) × 10^(multiplier band), with tolerance read from the 4th band's color. — so results are accurate every time, not an approximation.