Why Does Arduino Take So Long to Compile?

Why Does Arduino Take So Long to Compile?

Today, programming Arduino boards is becoming increasingly popular as a way to build custom electronics projects. While the language itself is relatively easy to learn, one of the common frustrations faced by many Arduino users is how long it takes their code to compile once they hit upload. When you’re in the middle of debugging an issue or trying to get your project up and running quickly, being forced to wait several minutes and potentially longer can be extremely exasperating. But why does it take so long for Arduino sketches and libraries to compile? In this blog post we’ll discuss what goes on behind-the-scenes when you upload code onto an Arduino board, so that next time your sketch compiles slowly you can rest assured knowing why!

What Is Arduino?

Arduino is a microcontroller development board that allows users to create interactive electronic projects. Its open-source platform makes it easy for anyone to get started with electronics and programming. It’s used by both professionals and hobbyists in the field of robotics, automation, and physical computing.

However, even though Arduino is designed to be user-friendly and accessible, one of the complaints users have is that compilation can take quite a while. This problem can be particularly frustrating if you’re just starting out or are trying to debug your code quickly. So why does Arduino take so long to compile?

What Is Arduino?

Causes of Slow Compilation of Arduino Code

Antivirus Program Interference

Antivirus programs, like any other software running in the background, can interfere with the compilation process of Arduino code and slow it down. To combat this issue, try temporarily disabling your antivirus while compiling and then re-enable it afterward.

Hardware Limitations

If you’re using an older or low-powered computer, its slower processor and lack of RAM may be causing the compilation to take longer than usual. For better results, consider upgrading your device or getting a more powerful one specifically for coding purposes.

Too Many Libraries

When writing code for Arduino, libraries are often used to add features and functionalities to projects. However, too many libraries can quickly become overwhelming for the compiler and cause it to slow down drastically. Try to keep the number of libraries used to a minimum in order to speed up the compilation process. [1]

Badly Written Code

If the code being written is overly complex and badly structured, it can take longer for the Arduino IDE to interpret and compile it correctly. To avoid this issue altogether, make sure your code is well-written and easy to read so that the compiler can quickly parse it without any trouble.

Outdated Firmware

Arduino boards usually come with their own set of firmware, which needs to be regularly updated in order for it to remain compatible with the latest versions of Arduino environments and libraries. If this firmware isn’t up-to-date, compiling code may take much longer than usual. Check your board’s firmware and update it accordingly.

Noisy Environment

Compiling code requires silence and concentration, so any external disturbances can slow down the process significantly. Whether it’s a loud fan or other noisy appliance in the room, make sure to switch them off temporarily while compiling Arduino codes. This will help speed up the compilation process significantly.

Causes of Slow Compilation of Arduino Code

To conclude, there are several reasons behind why Arduino takes so long to compile which includes antivirus interference, hardware limitations, too many libraries being used, badly written code, outdated firmware and a noisy environment. To speed up this process and ensure that projects are completed on time with minimal hassle, it is important to identify these issues and address them accordingly as soon as possible. [2]

How to Fix the Slow Compilation Issue of Arduino IDE?

The Arduino IDE is a great tool for programming your projects, but slow compilation can be an issue. It takes longer than necessary to compile and upload your sketches. Fortunately, there are some things you can do to help speed up the process.

  • Increase RAM: Increasing the amount of RAM available to the Arduino IDE will speed up compilation times considerably. There are easy ways to do this, such as going into the File > Preferences menu in the IDE and increasing the memory size allocated to it.
  • Update System Libraries: Outdated system libraries can cause issues with compilation, so make sure they’re always up-to-date by using an automated library manager like PlatformIO or manually updating them.
  • Disable Unnecessary Includes: When writing sketches, it’s important to only include the necessary libraries instead of including all the libraries you might need in a project. This helps reduce compilation time by significantly reducing the amount of code that needs to be processed at once.
  • Use Command Line Tools: The Arduino IDE isn’t the only way to compile and upload your sketches, as you can use command line tools such as avrdude or avr-gcc for faster results. These are more complex than using the IDE, but if you have experience with programming languages then this should come naturally.
  • Check RAM Usage: If there is still an issue after implementing some of the tips above, then you should check how much RAM is being used by each program and library. This can be done in the Arduino IDE by going to Tools > Report Memory Usage.

By following these steps, you should be able to significantly reduce compilation times and get your projects up and running much faster. With a few small tweaks, you can make sure that your Arduino IDE runs as smoothly as possible.

How to Fix the Slow Compilation Issue of Arduino IDE?

Use Smart Programming Methods

The answer to why Arduino takes so long to compile lies in the fact that it is an interpreted language, which means code is translated into machine language while running. This process can be time-consuming and requires optimization from the programmer.

To optimize your programs for faster compilation times, you will want to use smart programming methods such as:

  • Using macros instead of functions when possible: Macros are pieces of code that are pre-compiled by the Arduino IDE and stored in memory, meaning they can run more quickly than calling a function.
  • Minimizing scope: By minimizing scope (the amount of space a given variable or program occupies in memory), you can reduce the amount of processing time required to compile and run your code.
  • Optimizing your data structures: By optimizing the structure of the data you are storing in memory, you can reduce the time it takes for the compiler to process it. This could mean using an array instead of a linked list or structuring variables into groups for faster access.
  • Improving readability with comments: Comments are key for helping maintain code over a long period of time, but they also make it easier for compilers to parse code efficiently, which can lead to faster compilation times.

By following these methods and keeping an eye on the amount of processing power your programs require, you can help lessen compilation times and increase efficiency when working with Arduino programming. [3]

Avoid Adding Unnecessary Libraries and Components

Adding unnecessary libraries and components to your code can cause Arduino compilation to take longer than usual. Unneeded libraries or components will use up extra memory, thus slowing down the compilation process. Furthermore, they may also conflict with existing programs or hardware within your project. It is important to keep your code as lean as possible by removing any unnecessary elements that are not being used in the program. This will speed up the overall compilation time and make sure your project runs more efficiently.

Another way to avoid long Arduino compile times is to ensure that all of the parameters of each library you add are properly configured. Proper configuration ensures that no errors arise while compiling, which can significantly reduce the amount of time it takes for completion. Additionally, if you are using a library that has not been updated in a while, it can be useful to look for alternative libraries or find ways to update the existing one.

Outdated libraries can cause unnecessary delays and errors during compilation.

Finally, optimizing your code is also a great way to avoid long compile times on Arduino. By using fewer variables and functions, you can make sure that the code compiles quickly with no errors present. Additionally, making sure your code is organized and commented properly will help speed up the process as well. All these steps combined should help keep your Arduino compilation time low and efficient.

By following these steps, you can ensure that compiling an Arduino project doesn’t take too long of time and helps keep everything running smoothly. Keeping your code lean, making sure libraries are properly configured and optimized, and organizing your code can all contribute to faster compile times. This should make it easier to develop Arduino projects efficiently and quickly. [4]

Avoid Adding Unnecessary Libraries and Components

Pros and Cons of Arduino

Despite the fact that Arduino is an incredibly popular microcontroller platform, there are both pros and cons to its use. The most obvious pro of Arduino is its ease of use; it was designed to be a beginner-friendly solution for creating interactive projects. It is also very affordable compared to other platforms, which makes it more accessible to those on a budget. Additionally, Arduino has robust community support with plenty of online tutorials and resources available, making it easier for new users to get started quickly.

The main con of Arduino is that compiling sketches can take longer than other development platforms due to its limited processing power. This can be especially true when dealing with larger projects or ones using multiple libraries. Furthermore, some argue that the code written for Arduino is not as organized and efficient compared to other development platforms.

Finally, while the platform offers a lot of flexibility in terms of hardware compatibility, some say that its full potential can be difficult to reach due to lack of documentation and support for more complex projects. [5]

Pros and Cons of Arduino


Why does Arduino IDE take so long to load?

The Arduino IDE can take a long time to load because it needs to process and compile all the code in your project before execution. The larger the project, the more code there is for the IDE to process and compile, which increases loading times. Additionally, some older computers may be underpowered compared to newer models and therefore have slower processing speeds, further increasing loading times. To improve loading speed, you can try running fewer programs at once or reduce the size of your projects by removing any unnecessary files or using libraries that are optimized for faster compilation. Alternatively, you can try an alternative development environment like Visual Studio Code or PlatformIO that may have better optimization capabilities than Arduino IDE. You should also make sure your computer hardware meets the minimum system requirements for Arduino IDE and your projects.

Is Arduino code slow?

The answer is no. Arduino code executes quickly and efficiently. However, the Arduino IDE takes a long time to compile the code before it can be uploaded to the board. Compiling is the process of translating human readable code into machine-readable instructions for the microcontroller on your board. This requires that all of the necessary libraries and header files needed for your project are included in your program, which can take some time depending on how complex your project is. Additionally, if there are any errors or warnings within your code, they must also be addressed before compilation can begin. Therefore, compiling can take a while as all these elements need to be checked carefully by the compiler before it begins its job.

How do I stop Arduino from compiling?

Unfortunately, you cannot stop Arduino from compiling. However, there are a few things you can do to speed up the process and make your development experience more efficient. Firstly, try to keep the code in your project as simple as possible. Secondly, familiarize yourself with the libraries and header files that are needed for your project so you can easily add them when necessary. Additionally, if there are any errors or warnings in your code, address them immediately before beginning compilation.

What language is Arduino?

The Arduino programming language is based on Wiring, which is a simplified version of the C and C++ programming languages. The Wiring language was developed specifically for use with microcontroller boards such as the Arduino. It has been designed to be easy to learn and use, making it accessible to beginners and experienced coders alike. Ultimately, understanding why compiling takes so long can help you become a more efficient programmer. By following best practices and ensuring that all required libraries are included in your code, you can speed up the compilation process and make development smoother. Additionally, familiarizing yourself with the Arduino programming language can help you better understand how your code works and reduce compile times even further.

Is Arduino code C or C++?

Arduino code can be written in either C or C++. Arduino uses a modified version of the underlying language, which is known as the Arduino Language. The core language of Arduino programming is based on wiring and contains some additional features like string manipulation and math operations that make it easier to work with. Even though it has been modified to make it user-friendly, most of the commands used are still based on standard C/C++ functions.

Useful Video: Double your Arduino IDE Compiling Speed – ESP32, Arduino


In conclusion, Arduino takes a long time to compile due to the complexity of the code, the limitations of the hardware, and other factors. While there may be ways to reduce this time, it is important to keep in mind that optimizing your code can help make compilation faster and smoother. Additionally, using an external editor such as Visual Studio Code can also help speed up compilation times. Ultimately, while it may take longer than other development platforms, Arduino’s unique features and flexibility make it worth the wait.


  1. https://support.arduino.cc/hc/en-us/articles/7213793867036-Improve-compilation-time-with-Arduino-IDE
  2. https://linuxhint.com/arduino-takes-long-compile-fixes/
  3. https://forum.arduino.cc/t/why-is-compilation-so-slow/477307
  4. https://github.com/arduino/arduino-ide/issues/788
  5. https://rntlab.com/question/long-compile-time-for-esp32-on-arduino-ide/