There have been over 15 Arduino boards released since the microcontroller series began in 2005. The Arduino Mega and Uno are two of the most popular and widely used Arduino boards.
Each board has certain features and peculiarities that make it better suited for certain tasks than the other. We’ll explore these differences in detail and help you decide which of these boards is better suited for your electronics project. Arduino Uno vs Mega: let the Arduino comparison begin…
Arduino Mega
The Arduino Mega was initially released in 2009 and is now in its third revision with the Arduino Mega 2560 Rev3. The current Mega is powered by an ATmega 2560 microcontroller and uses an ATmega16U2 chip to convert USB signals to serial instructions. Check out our guide tomastering serial communication with Arduino.
The Arduino Mega 2560 has 54 digital I/O pins in total (15 of which provide PWM output), along with 16 analog inputs. It also features hardware serial ports, a barrel plug connector, and a USB-B port.
It can be powered from either the USB port or the power jack and is capable of operating on a power supply ranging from 6 to 20 volts. The ATmega 2560 operates at a clock speed of 16MHz and offers 8kB of SRAM, 256kB of flash memory, and 4kB of EEPROM.
The Mega 2560 is compatible with most shields designed for the Uno and the former boards Duemilanove and Diecimila. This means that shields created for these boards will also work on the Mega.
you’re able to get the Arduino Mega 2560 from the official Arduino store for about $35, about the same price as the 1GB variant of the Raspberry Pi 4.
Arduino Uno
The Arduino Uno is by far the most popular Arduino board, and it is also the one most beginners use to venture into the world of tinkering with electronics. The Uno Rev3 (aka Uno R3) has an 8-bit processor, operates at a clock speed of 16MHz, and can be powered from either the USB-B port or the power jack connector, the same as the Mega.
However, it has less of everything else, with only 14 digital I/O pins, 6 analog inputs, and only a single UART port. The Uno R3 board uses the ATmega 328P chip and has 2kB SRAM, 32kB flash memory, and 1kB EEPROM. It has an operating voltage ranging from 2.7 to 5.5 volts.
The Uno is the most documented Arduino board. The vast majority of Arduino electronics tutorials you will find online will be using the Arduino Uno to control other electronic components. The Uno R3 is available at the official Arduino store for around $28.
The newArduino R4 modelfeatures a much more powerful 32-bit processor, upgraded storage, and comes in two variants.
Arduino Mega vs. Uno: Size
The Arduino Mega stays true to its name and is about twice the width of the Uno at 4 x 2.1 inches, mainly due to the increased number of pins and its larger memory. The Arduino Uno, on the other hand, is built for portability and measures 2.7 x 2.1 inches. The Arduino Mega and Uno weigh about 1.3 oz and 0.88 oz, respectively.
The Arduino Uno is therefore a better option for projects with a size limitation, such as gaming devices and other portable projects. If size is not a major consideration for you, then the Arduino Mega could be the microcontroller for your project.
Arduino boards come in a wide range of shapes and sizes, so be sure to check out ourguide to the various types of Arduino microcontrollersavailable.
Arduino Mega vs. Uno: Price
The Arduino Mega is also more expensive than the Uno. At official retail prices, the Mega costs about $35, much more than the Uno which is usually sold for around $25. Although the Arduino Mega is not the most expensive microcontroller board, it may not be worth it for your project if your primary concern is minimizing cost.
The Arduino Uno R3, on the other hand, is quite affordable, making it the ideal choice for beginners interested in playing around with the platform without worrying about breaking the board.
Connectivity and Memory
The Mega features more connectivity options than the Uno, which means it is a better choice for projects that require a ton of I/O. For example, in a robotics project where you might need to connect several servos and actuators or when building a DIY 3D printer where the Arduino Mega acts as the main controller.
Not all projects require the extra I/O pins though, so the Arduino Uno should work well enough for most of the projects you encounter, especially as a beginner.
The Arduino Uno Rev3 has less memory than the Mega, limiting the size of the code you can upload and run. The Mega also has more SRAM, making it capable of storing more runtime data (variables and their values). This makes it better suited for running more complicated programs than you would be able to run on a Uno.
Hardware Specs Compared
To make it easier to see the differences between the Arduino Uno and Mega at a glance, we’ve listed the hardware features of both boards below side-by-side.
Arduino Uno Rev3
Arduino Mega Rev3
Microcontroller
ATmega328P, 8-bit
ATmega2560, 8-bit
Clock Speed
Operating Voltage
Input Voltage (recommended)
Input Voltage (limits)
Digital I/O pins
14 (of which 6 provide PWM output
54 (of which 15 provide PWM output)
Analog Input pins
Flash Memory
Popularity and Community
Unarguably, the Arduino Uno is the more popular of the two boards, making up about 50% of Arduino board usage, according toSparkFun Electronics. It is readily available and widely used, making finding tutorials tailored for the board easier. The Mega is less popular and so that may be inconvenient if you’re just getting started.
However, the Mega 2560 is designed to be compatible with the Uno. Therefore, all code and most hardware created for the Uno will work perfectly with the Mega. But, not all code and shields designed for the Mega will work with the Uno due to the increased number of pins on the Mega.
Which One Should You Use?
In conclusion, both boards are excellent options for tinkering with electronics, robotics, and Internet of Things (IoT) applications (with the addition of a Wi-Fi shield).
The Arduino Uno is a better option for beginners due to its low cost, small size (making it a better fit for smaller hands), and overall ubiquity. The Mega, on the other hand, is excellent for projects that require extra I/O pins, computing power, and memory, making it perfect for hobbyists who have already gotten their feet wet.
