LED Resistor Calculator

Calculate the required resistor value for your LED circuit.

V
V
mA
Resistor Value: -
Resistor Power: -

Instructions

How to Use:

  • Enter Source Voltage (e.g., 5V, 9V battery).
  • Enter LED Forward Voltage (typically 2V for Red, 3V for Blue/White).
  • Enter LED Current (typically 20mA).
  • Click Calculate to find the resistor value.

Tip: Always choose the next highest standard resistor value.