ENGINEERING / FREE ONLINE TOOL
LED Series Resistor Calculator
Estimate an LED current-limiting resistor and dissipation.
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A little guidance.
Use R = (Vs − Vf) / I to estimate an ideal series resistor for one LED. The supply must exceed the LED forward voltage. Reported power is calculated dissipation, not a recommended component rating; allow suitable design margin and check the LED datasheet.
How it works
- Enter your values, or use the example to get started.
- Select “Calculate” to process your input in your browser.
- Review the result, then copy or download it when available.
Good to know.
Is my input sent to a server?
No. This tool runs in your browser. KILIZU does not upload or store the values or files you enter here.