Resistor Color Code Calculator

Decode 4-band and 5-band resistor color codes to find resistance and tolerance.

Select…

Select…

Select…

Select…

Related Tools

🔢
Binary ↔ Decimal ↔ Hex Converter
Convert numbers between binary, octal, decimal and hexadecimal at once.
 🆔
UUID Generator
Generate cryptographically random UUID v4 identifiers, one or many at a time.
 🔗
URL Parser
Break a URL into its protocol, host, path, query parameters and more.

0 comments

How it works

Select 4-band or 5-band mode, then click the color for each band. For 4-band: bands 1–2 are digits, band 3 is the multiplier, band 4 is tolerance. For 5-band: bands 1–3 are digits, band 4 is the multiplier, band 5 is tolerance. The tool computes the nominal resistance in ohms and shows the minimum/maximum values based on the tolerance band. All calculation runs locally in your browser.

Common use cases

  • Identifying the value of an unmarked resistor pulled from a parts bin.
  • Verifying a resistor value before placing it in a circuit.
  • Learning the resistor color code through interactive selection.

Frequently asked questions

Which end do I start reading from?

Start from the end with the band closest to the edge of the resistor body. The tolerance band (gold, silver, or none) is always last and is usually spaced farther from the others.

What does tolerance mean?

Tolerance is the allowed variation from the nominal value. A 100 Ω resistor with ±5% tolerance can measure anywhere from 95 Ω to 105 Ω and still be within spec.