How to Convert Decimal Number to Hexadecimal Using Arduino

Arduino programming has multiple functions to read and manipulate data using serial communication. Using these functions, we can design different Arduino projects and create a real time solution. One common task when working with microcontrollers is to convert decimal numbers to hexadecimal format. In this article, we will explore how to convert decimal numbers to hexadecimal using Arduino, step by step.

Introduction to Number System in Arduino

Before diving into the process of converting decimal numbers to hexadecimal using Arduino, it’s essential to understand the basics of the two number systems.

  • Decimal is a base-10 numbering system. This means that decimal numbers use ten digits (0-9)
  • Hexadecimal is a base-16 numbering system. These numbers use sixteen digits (0-9, A-F)

Convert a Decimal Number to Hexadecimal Using Arduino Code

To convert a decimal number to hexadecimal using Arduino code we can use the built-in function toHex(). This function takes decimal as input and returns the hexadecimal number in a string.

The resulting hexadecimal value can then be printed to the serial monitor or used in further calculations within the Arduino sketch.

Arduino Code for Decimal to Hexadecimal Converter

Below given is the Arduino code that converts a user input number to hexadecimal:

void setup() {
  Serial.begin(9600); // initialize serial communication at 9600 baud

void loop() {
  long decimal_input;
  // prompt the user for a decimal input
  Serial.println("Enter a decimal number:");
  // wait for input from the user
  while (Serial.available() == 0) {}
  // read the decimal input from the user
  decimal_input = Serial.parseInt();
  // convert the decimal input to hexadecimal and print it
  Serial.print("The hexadecimal equivalent of ");
  Serial.print(" is 0x");
  Serial.println(decimal_input, HEX);

In the setup() function, we started by defining serial communication. Next in loop() function, we define an integer variable decimal_input to hold the user’s input.

We prompt the user to enter a decimal number by printing a message to the serial monitor. Next program will wait to receive the user input using the Serial.available() function, which gives the total bytes that are available to read.

Once input is available, we read the decimal input using the Serial.parseInt() function. The decimal input is converted to hexadecimal using the HEX option in the Serial.println() function.

Finally, the converted Hexadecimal number is printed on the serial monitor.

Uses of Arduino Based Decimal to Hexadecimal Converter

Here are five uses of decimal to hexadecimal number converter using Arduino:

Displaying sensor readings: Many sensors output data in decimal format, which can be converted to hexadecimal before displaying on an LED or LCD display using Arduino.

Communicating with other devices: Most of the communication between Arduino and other devices is done using the Hexadecimal number or format. For that we need to convert decimal to Hexadecimal.

Addressing memory locations: Memory addresses in computers are generally displayed in hexadecimal.

Performing bitwise operations: Bitwise operations such as shifting and masking are often performed using hexadecimal numbers.


Converting decimal numbers to hexadecimal using Arduino is a simple process that can be done using the Serial.println() function along with the default toHex() Arduino function. The steps explained in this writeup will help to easily convert decimal numbers to hexadecimal.

About the author


I am an Electrical Engineer. I love to write about electronics. I am passionate about writing and sharing new ideas related to emerging technologies in the field of electronics.