How to use led resistor calculator
Estimate a series resistor and dissipation from supply voltage, LED drop and current. This browser tool shows the inputs, assumptions and resulting output so you can use it for a specific everyday task.
- Enter your own values or choose a supported file.
- Adjust the options and run the tool.
- Review the result, then copy, export or save it when available.
Try this next
Estimate a resistor for a 5 V supply, 2 V LED forward drop and 20 mA current.
Use component datasheets and appropriate ratings. The calculator assumes a simple low-voltage DC series circuit and does not design a mains supply.
Questions, answered.
Is led resistor calculator free to use?
Yes. This tool is part of Nepocore’s free browser toolkit. There is no paid tier, file-download gate or application account required.
What should I check before using the result?
Use component datasheets and appropriate ratings. The calculator assumes a simple low-voltage DC series circuit and does not design a mains supply.
Does this tool upload my files or text?
The tool processes its input in your browser. File contents and text are not sent to a processing server. See the privacy page for local storage and hosting details.