Arduino Uno vs. Nano: Which Board Is Better?

My first board was an Arduino UNO. I explored other Arduino options and found the Nano to be one of the best ones out there. So, I thought I’d write an article to share my learnings in the form of a comparison between the two amazing Arduino boards: UNO and Nano.

Arduino Uno vs. Nano: Which Board Is Better? Each board offers a different set of pros and cons, which makes it challenging to pick one board out of the two. It mainly depends on your project’s application. Some projects demand the use of Arduino Nano while others especially require the Arduino Uno board.

My Arduino UNO WiFi Rev 3

The compact Arduino Nano is ideal for projects where size is an issue, while Arduino Uno does not have such restrictions. Similarly, there are many other aspects on which the two boards are comparable. Below, I’ll cover these aspects and discuss the features of each board separately so that by the end of this article, it’ll be easier for you to decide which board to use in your upcoming project. 

Looking for the best Arduino for beginners? I wrote a complete guide comparing costs and features of the best boards for beginners here:

What Is The Arduino Nano?

To compare the two boards, you must first know what the Arduino Nano is. It is a powerful yet very compact microcontroller board, almost half the length of an Uno board. It is one of the most widely used Arduino boards all around the world, mainly because of its unique physical dimensions. It is convenient in situations where you are looking for a board that can fit into tiny spaces without any hassle since it is breadboard friendly. 

Similar to other Arduino boards, it has digital and analog I/O pins along with power, GND, and reset pins. However, it does not have a regular USB dock; instead, it has a micro USB port to connect it with a computer/laptop. Arduino Nano has all the functionalities of other Arduino boards with an added advantage of compact size.

How Reliable Is Arduino Nano?

You can use Arduino Nano in a wide variety of projects ranging from simple LED blinking projects to complex IoT applications. It is controlled by the powerful ATMEGA328 chip, which offers a clock speed of 16 MHz, just as much as other Arduino boards. Hence, you can rely on Arduino Nano for all your electronic project needs; whether you are a student or an electronic hobbyist, this board offers everything that you need.

Arduino Uno vs. Nano 

To see how well Arduino Nano works, let’s compare it with the viral Arduino Uno board, which many people believe is their go-to microcontroller board. The Uno board has everything that you would want in a basic microcontroller board. Let’s see how it compares with the Arduino Nano.


Arduino Nano and Uno both have 14 digital I/O pins, while the Analog I/O pins are not equal. Arduino Nano has 8 analog pins while the Uno board has 6 of them. Both boards have the same power pins; 5V, 3.3V, GND, and Vin. 

Now let’s look at some of the significant differences between the two boards. The first one is the absence of a DC barrel connector in the Nano board, which is a handy feature when it comes to powering Arduino without a battery. The UNO board, however, has the option of powering it via a DC adaptor. 

The second significant difference between the two boards is in the USB port. Arduino Nano has a micro-USB port that connects it to the computer, while the Uno board uses an A/B USB connector. The designers must have used a smaller USB port for the Nano board because of its small size and delicate PCB. The regular USB port wouldn’t have looked as good on the nano board as it does on the Arduino Uno. 

Power Consumption

The power consumed by Arduino Nano, according to the official Arduino website, is 19 mA. The current per I/O pin is 40 mA, whereas, for the Uno board, it is 20 mA. The power consumption mainly depends on the number of modules you attach to your Arduino since a higher amount of current drawn means that your project requires more power.  


Arduino Nano is a 45 mm-long board, with a with of 18 mm. On the other hand, the Uno board is 68.6 mm long and has a width of 53.4 mm. The width of the Arduino Nano is approximately one-third of the Uno board, which is a very significant difference. It means that if you are finding it difficult to fit the Uno board in your project because of its width, then you can opt for Arduino Nano to solve the problem. 

Since the Arduino Nano board is much smaller than the Uno board, it weighs a lot lesser as well. If you are looking for a lightweight microcontroller, then Arduino Nano is what you should opt for because it weighs only 7 grams! Whereas the Uno board weighs a total of 25 grams. Typically, IoT based applications require a lightweight microcontroller, and that’s where you can use an Arduino Nano. 


The ATMEGA328P powers the Arduino Uno, while a slightly different version of the same processor, ATMEGA328, powers the Arduino Nano board. The most significant difference between these two processors is their power consumption. ATMEGA328P uses less energy as compared to ATMEGA328, which means that Arduino UNO has a lower power consumption than the Nano board.  

If you compare the flash memory, EEPROM, and SRAM of the two boards, you will notice that they are precisely the same. Hence, if you are choosing one of the two boards based on some memory requirements, then you should know that there is no difference between the two in this regard.

Arduino MEGA vs.Nano

Since we have just compared the Arduino Nano with Uno, let’s also see how the Arduino Nano compares with the Arduino MEGA. 


If you look at the pinout of Arduino MEGA, you will notice that it has twice as many analog pins as compared to the nano board. Similarly, Arduino MEGA has 54 digital I/O pins, much higher in number than the Arduino Nano, which has only 14 digital pins. 

Similar to Arduino UNO, Arduino MEGA also has a DC power jack (barrel connector) and a larger USB port as compared to Arduino Nano. The power and ground pins of Arduino MEGA are similar to those of Arduino Nano.


Arduino Nano is a significantly smaller board as compared to Arduino MEGA. To be precise, Arduino MEGA is 101.52 mm long and 53.3 mm wide, whereas the Nano board is 18 x 45 mm, very short and delicate as compared to Arduino MEGA. 

Similarly, if we compare the weights of the two boards, Arduino MEGA weighs 37 grams while Nano weighs only 7 grams. That’s a significant difference, so if weight is an issue for your Arduino project, then you can certainly opt for a Nano board instead of the bulk Arduino MEGA. 


Arduino MEGA is powered by the powerful ATMEGA560, whereas the ATMEGA328 powers the Nano board. The CPU speed for both boards is the same, 16 MHz. However, memory specifications are quite different. The Arduino MEGA has a flash memory of 256 kB and an EEPROM of 4 kB plus an SRAM of 2 kB. The nano board has a flash memory of 32 kB, EEPROM of 1 kB, and a 2 kB SRAM; this proves that Arduino MEGA has a better processing capability as compared to Arduino Nano. 

Can I Use Arduino Uno Instead of Nano?

If we consider the processing power of Arduino UNO and Nano, then there is not much difference between the two. Both boards can process the same amount of commands at a time, and they have the same pin configuration as well. However, their dimensions are quite different. So, can you use an Arduino Uno instead of Nano? Well, if the size is not an issue, then you can consider Uno as a replacement for the Arduino Nano. On the contrary, if you are building a project where you need to fit the microcontroller board in a small space, then you cannot replace Arduino Nano.

Which Is Best For Beginners: Arduino Uno or Nano?

If you are a beginner, who is looking forward to learning Arduino programming and interfacing, then Arduino UNO is the best choice for you. Almost all beginners use Arduino UNO as their first microcontroller board and then move towards the other boards as they fain experience. Compared to Arduino Nano, Uno is a user-friendly board because it has a regular USB port and a DC barrel connector. 

Moreover, you need to pop the Nano board into a breadboard while using it because it has all-male headers. Arduino UNO has female headers that require jumper wires to connect to other modules and devices. Using a breadboard can be confusing for beginners as compared to using jumper wires for making connections. 

It’s totally up to you to select a microcontroller, but I would suggest that you go for an Uno board if you are a beginner. It also has better safety options; for instance, if you accidentally fry the processor chip, you can plug it out and insert a new one. But if you fry the Arduino Nano chip, then it would be difficult for you to reverse the damage. 

Similarly, with all-male headers in the Arduino Nano board, the chances of short-circuiting two or more pins together are very high. Female headers are safe since the conducting part of the pins is enclosed inside the insulated header railing. 

Arduino Uno vs. Nano Projects

As you are already aware by now, of the difference in size between the two boards, Arduino Nano is better suited for applications where size is a concern, and the project components need to fit into a small place. Some typical Arduino Nano applications are listed below:

  • Mini Robots
  • Digital Clock
  • IR Remote Control
  • Weather Shield
  • Wearable Items (Heart Rate Monitor)
  • Security Systems

On the other hand, you can use Arduino Uno in almost every other project. Whether you need to build a simple LED blinking project or a complex IoT-based project, Arduino Uno will always save the day. Here are some of the most popular Arduino UNO applications:

  • Line Following Robot
  • Obstacle Avoiding Robot
  • Home Automation System
  • Laser Security System
  • Firefighting Robot

Which Board Is Better? 

You cannot say which board is better. It depends on your application since each of the two boards have their pros and cons. Arduino Nano offers the advantage of compact size at the expense of the option of powering the Arduino with a DC adaptor. On the other hand, Arduino Uno has the advantage of using a regular USB connector, as compared to Arduino Nano, which requires a micro-USB cable that you’d have to make an effort to find. Moreover, you need an additional piece of equipment – a breadboard – to use Arduino Nano because it has only male headers, while Arduino UNO is much easier to use. 

If you know which project you are going to work on next, then it will be easier for you to decide which board to choose. Once you have clearly understood the project requirements, you can easily weigh the pros and cons of each board and see which one is better. No one can declare that Arduino Uno is better than Nano, or vice versa. It all depends on the application.

I hope you have understood the differences between the two boards, and this article has helped you build a clear picture of both boards in your mind. If you ever need to choose between the two boards, then always weigh the advantages and disadvantages that the two boards are offering. That is what I have always done before working on any project.


Engineer and electronics enthusiast. Enjoys solving problems with electronics and programming.

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