Resistor color code calculator

Choose resistor band colors to calculate resistance and tolerance.

On your device · No account

Privacy details

Resistor color code calculator processes your input in this browser. Inputs and results are excluded from analytics. Recent tools save tool names, visit counts and last-visit times. Saved tools store only their names. Draft saving is optional and stays on this device; delete saved text with the draft controls. Loading text from a URL is optional and contacts that server; its URL and your IP address are visible to the server. An optional “Use in” action keeps a handoff in this tab. The next tool removes it on arrival and ignores it if more than a minute has passed.

Copy link includes the inputs you choose to share in the address. Anyone with that link can reopen them. Files and generated results are excluded. Password and key tools share settings only.

Number of bands

Band colors

First digit

Second digit

Third digit (5 bands only)

Multiplier

Tolerance

Your result

Enter your values.

Reset reloads the tool with its starting values and releases open files and device controls. Saved drafts stay on this device until you delete them.

Links include your inputs and settings. Anyone with the link can see them, so leave out private text. Files and generated results are left out; random draws run again.

Keyboard shortcuts

Updated 2026-09-19

Using the resistor color code calculator

In a four-band code, the first two bands form the significant digits. A five-band code uses three digits. The next band is the multiplier and the last band gives tolerance. Read from the end with the grouped significant digits.

A worked example

Brown, black, red and gold give 10 × 100 = 1,000 ohms, with a tolerance of ±5%.

Before you use the result

This decodes color markings, not a resistance measurement. Faded colors and special resistor markings may be ambiguous. Check the component documentation before using the result.

Next: Color picker

Cite this page

Citation style

ToolOctopus. “Resistor color code calculator.” Updated 2026-09-19. https://tooloctopus.com/resistor-color-code-calculator.

Add an access date if your instructions require one.

Citation formatting uses citeproc-js by Frank Bennett and Citation Style Language styles. Licence and source code.