Arduino Uno vs Arduino Mega – Which one to choose?

The Following table shows the comparison between the three popular Arduino boards. It is primarily a comparison between Arduino Uno vs Mega 2560.  Note that the Arduino Mega 1280 is now super seeded by the newer Arduino Mega 2560. The Atmel AVR ATmega2560 has more on chip resources (FLASH, SRAM, and EEPROM)

Features	Arduino Uno	Arduino Mega (1280)	Arduino Mega 2560
Microcontroller (MCU)	ATmega328P (Datasheet)	ATmega1280	ATmega2560 (Datasheet)
Operating Voltage of the Microcontroller	5 V	5 V	5 V
Typical Supply Voltage for the board	7 V – 12V	7 V – 12 V	7 V – 12 V
Digital I/O Pins	14 (includes 6 PWM outputs)	54 (includes 15 PWM outputs)	54 (includes 15 PWM outputs)
PWM outputs	6	15	15
Analogue Input Pins	6	16	16
Max DC Current per I/O Pin	20 mA	20 mA	20 mA
Max DC Current for 3.3V Pin	50 mA	50 mA	50 mA
Flash memory of MCU	32 KB	128 KB	256 KB
Bootloader footprint	0.5 KB	4 KB	8 KB
SRAM of MCU	2 KB	8 KB	8 KB
EEPROM of MCU	1 KB	4 KB	4 KB
Clock Speed	16 MHz	16 MHz	16 MHz
Board Dimensions (Length)	68.6 mm	101.5 mm	101.5 mm
Board Dimensions (Width)	53.4 mm	53.4 mm	53.4 mm
Cost	Typically $10	Typically $20	Typically $20

Recommendation

If you want to write considerably complex programs involving Ethernet shields and Micro SD cards it is recommended to go for Arduino Mega 2560 board. Be aware, this board is almost twice as expensive as Arduino Uno.

If you are just getting started with Arduino, or if you want to create simple applications such as temperature sensor, gps interfacing, stepper motor control, alarm system, interface accelerometer, – You should go for Arduino Uno!