# LED resistor calculator

Canonical page: https://nepocore.com/tools/led-resistor/

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.

## How to use it

1. Enter your own values or choose a supported file.
2. Adjust the options and run the tool.
3. Review the result, then copy, export or save it when available.

## Example

Estimate a resistor for a 5 V supply, 2 V LED forward drop and 20 mA current.

## Limits and checks

Use component datasheets and appropriate ratings. The calculator assumes a simple low-voltage DC series circuit and does not design a mains supply.

## Access and processing

Free to use without an account. Interactive processing requires JavaScript in a modern browser. Input is processed in the browser rather than sent to a processing server. Optional browser storage is not a synchronized account.


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