What Is the Difference Between Digital and Analog Pins?

Digital pins read or write two states. Analog pins measure a range of values. That is the core difference.

Digital pins

  • Input: Reads HIGH or LOW.
  • Output: Writes HIGH or LOW.
  • Use for: Buttons, switches, relays, basic LEDs.

Analog pins

  • Input: Reads a range of voltage levels.
  • Use for: Sensors like light, temperature, and potentiometers.
  • Typical range: 0 to 1023 on many Arduino boards.
Bottom line

Digital is on or off. Analog is a range. Pick the pin type based on the kind of signal you need.

Related: Why does analogRead give values 0 to 1023? · Can I use analog pins as digital pins? · What is PWM and why is my LED flickering?