LED series resistor

How the calculation works

Choose an LED current-limiting resistor and check its minimum power rating. The tool converts the form units and presents the result using readable engineering notation.

R = (Vₛ − n × Vƒ) / I

Example

For 5 V, one 3.0 V white LED and 10 mA, the result is 200 Ω; choose the next higher standard value.

How to interpret the result

• LED forward voltage depends on colour, temperature and actual current.
• Choosing the next higher resistor value reduces overcurrent risk.
• Parallel LED branches should normally have separate current limiting.

Limitations and safe use

The result uses a simplified model. Check tolerance, temperature, absolute ratings and the component datasheet.