# Resistor Color Code

> Decode the resistance value and tolerance of axial resistors using the standard electronic color code system.

Page: https://askcalculators.com/calculator/resistor-calculator/
Definition: https://askcalculators.com/calculator/resistor-calculator/definition.json
JSON Schema: https://askcalculators.com/calculator/resistor-calculator/schema.json
Version: 7.0.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/calculator/resistor-calculator/?numBands=4&band=1

## Inputs
- numBands: Band count; type=select; optional; default=4
- band: Band; type=text; optional; default=1

## Outputs
- result: Result; format=text; primary

## Formula
Four-band resistance = first two digits × multiplier with the selected tolerance; color bands and ohms are converted both ways.

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.