How it works
Fill in the 3 fields above and LED Resistor Calculator calculates the result instantly, recalculating as you change any value. It applies the formula R = (Vs − Vled) / I. The math runs locally in your browser — nothing is sent to a server.
Formula
R = (Vs − Vled) / IExamples
- Supply voltage 5 V, LED voltage 2 V, LED current 20 mA → Resistor: 150 Ω
Frequently asked questions
How do I use the LED Resistor Calculator?
Enter your values in the 3 input fields and the result is calculated automatically as you type. Change any value to see the numbers update instantly.
What formula does the LED Resistor Calculator use?
It uses R = (Vs − Vled) / I. The calculation is performed in your browser using standard, well-established math for accurate results.
Is my data private?
Yes. The LED Resistor Calculator runs entirely in your browser. Nothing you enter is uploaded, saved to a server, or shared — it never leaves your device.
Is the LED Resistor Calculator free?
Yes, it is completely free with no sign-up, no limits and no watermarks. Like every tool on electronics and the rest of the platform, you can use it as often as you like.
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