LED Resistor Calculator

Estimate DC ballast resistance and resistor power using ideal LED model — screening only, not a datasheet replacement.

Free · No limits · Runs in your browser

How to use

  1. 1Enter supply and LED forward voltage.
  2. 2Enter target current in mA.
  3. 3Read R and power.

Frequently asked questions

PWM?
Average current differs from peak; this tool is steady-state DC.

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