Free calculators and converters that make your games & screens smarter.

Technicians, students and makers combine LED resistor, series resistor, parallel resistor and colour band decoding tools on one page for bench and classroom work. Decode four- and five-band codes under good lighting, totalise networks, and pick nearest standard E-series values when you only have a mixed parts kit on hand. LED, series, parallel and colour-band modes run locally, which suits homework, repair tickets and hobby logs you want to keep private.

Photograph colour bands before you desolder when codes might scorch, and double-check band orientation because a reversed reading can be orders of magnitude wrong. Use the LED helper alongside measured forward voltage rather than datasheet typicals alone when current accuracy matters for display brightness or battery life.