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What is the difference between Arduino Nano and Arduino Micro?


Arduino is an open-source electronics platform that uses easy-to-program microcontroller boards and software. The Arduino Nano and Arduino Micro are two popular small-form-factor boards in the Arduino family. They provide compact, breadboard-friendly options for Arduino projects.

But what exactly are the differences between the Nano and Micro? This guide examines the key distinctions in their specifications, design, hardware, and performance to help you select the right board for your needs.

Arduino Nano Overview

The Arduino Nano is one of the smallest classic Arduino boards, but still includes the essential components needed for many projects. Here are some key features:

  • Microcontroller: ATmega328P
  • Operating Voltage: 5V
  • Digital I/O Pins: 22
  • Analog Input Pins: 8
  • Flash Memory: 32 KB
  • Clock Speed: 16 MHz
  • Physical Size: 18 x 45 mm
  • Mounting Holes: No

The Nano’s small size makes it well suited for breadboard use and space-constrained projects. Its pin layout mirrors a standard Arduino Uno for easy migration between the boards. Overall, the Nano offers a versatile, economic option for many entry-level and intermediate Arduino applications.

Arduino Micro Overview

The Arduino Micro is even smaller than the Nano but contains more powerful processor and networking capabilities. Key features include:

  • Microcontroller: ATmega32U4
  • Operating Voltage: 5V
  • Digital I/O Pins: 20
  • Analog Input Pins: 12
  • Flash Memory: 32 KB
  • Clock Speed: 16 MHz
  • Physical Size: 18 x 33 mm
  • Mounting Holes: Yes

The Micro runs on the more advanced 32U4 processor, adding built-in USB communication support. Its compact stamped form factor consumes minimal space. These advantages make the Micro a good choice for projects involving USB connectivity or advanced processing in a tiny package.

Hardware Comparison

While the Nano and Micro share similarities in being small Arduino boards, they differ significantly in their hardware design and component integration.


  • Nano: ATmega328P – Common 8-bit AVR MCU, basic Arduino controller
  • Micro: ATmega32U4 – Enhanced 8-bit AVR with built-in USB support

The 32U4 gives the Micro native USB communication capability lacking on the 328P Nano.

Input/Output Pins

  • Nano Digital I/O: 22 pins
  • Nano Analog In: 8 pins
  • Nano PWM channels: 6
  • Micro Digital I/O: 20 pins
  • Micro Analog In: 12 pins
  • Micro PWM channels: 7

The Micro has 12 analog inputs versus 8 on the Nano, useful for more complex analog sensor applications.

Memory and Clock Speed

  • Nano Flash Memory: 32 KB
  • Nano SRAM: 2 KB
  • Nano EEPROM: 1 KB
  • Nano Clock Speed: 16 MHz
  • Micro Flash Memory: 32 KB
  • Micro SRAM: 2.5 KB
  • Micro EEPROM: 1 KB
  • Micro Clock Speed: 16 MHz

The memory configurations are nearly identical, with the Micro having slightly more SRAM. Both operate at 16 MHz.


  • Nano Input Voltage: 5-12V recommended, 7-12V required for some functions
  • Nano Power Connector: Mini-B USB
  • Micro Input Voltage: 5-12V recommended, 7-12V required for some functions
  • Micro Power Connector: Micro-B USB

The Nano and Micro both operate on 5V logic but can accept higher input voltages. The Micro uses the smaller Micro-B USB connector.

Physical Size and Form Factor

  • Nano Length x Width: 18 x 45 mm
  • Nano Mounting Holes: No
  • Nano Form Factor: Rectangular PCB
  • Micro Length x Width: 18 x 33 mm
  • Micro Mounting Holes: Yes
  • Micro Form Factor: Stamped assembly with integrated USB connector

The Micro has a smaller footprint than the Nano. The stamped design with integrated USB plug provides a more compact and rugged physical package.

Other Peripheral Hardware

  • Nano: No additional components beyond the microcontroller and basic I/O.
  • Micro: Integrated reset button and onboard LED; additional MCU peripherals like UART, SPI, I2C supported.

The Micro design incorporates some built-in user interface features and takes advantage of the 32U4’s peripherals.

Software Comparison

The Nano and Micro also use different processor families that impact compatibility with Arduino software libraries and cores.

Processor Family

  • Nano: ATmega328P (AVR 8-bit MCU)
  • Micro: ATmega32U4 (AVR 8-bit MCU)

Both are Atmel AVR chips but they require different cores to provide USB support on the Micro versus UART on the Nano.

Arduino Cores

  • Nano: ATmega328P core
  • Micro: Leonardo core

The Leonardo core adds USB communication libraries. Most shields and libraries are compatible with both cores.

Pin Mapping

  • Nano: ATmega328P Arduino pinout
  • Micro: ATmega32U4 Arduino pinout

Code written for Nano will need pin number changes to run on Micro. The pin functions match between boards but not pin locations.

Memory Management

  • Nano: Standard Arduino memory management
  • Micro: Enhanced memory management in Leonardo core

The Micro can more efficiently utilize its SRAM memory space than the Nano with the 328P core.

Performance Comparison

The Nano and Micro overall have generally comparable performance, but the Micro’s 32U4 architecture and USB support provide some advantages for specific use cases.

Processing Speed

  • Nano and Micro: Both 16 MHz clock speed

The two boards operate at the same 16 MHz frequency and thus equivalent raw processing rates.

Input/Output Speed

  • Nano: Standard I/O performance
  • Micro: Slightly faster I/O operation for analog and PWM functions

The 32U4 MCU implements some peripheral functions like ADC and timers in a more optimized fashion.

Interface Speed

  • Nano: UART capped at 2 Mbps
  • Micro: Hi-speed USB 2.0 with transfer rates up to 480 Mbps

The Micro’s integrated USB connectivity provides vastly faster throughput than the UART interface on the Nano.


  • Nano: Some delays managing USB-serial coordination
  • Micro: Native USB operation avoids UART delays

USB HID allows lower latency control of the Micro from a host computer compared to Nano’s conversion between USB and serial.

Program Storage

  • Nano: 32 KB flash for storing sketches
  • Micro: 32 KB flash for storing sketches

Both provide the same size 32 KB flash memory for storing Arduino sketches.

Cost Comparison

The Nano and Micro have similar manufacturing costs in the same low price range:

  • Arduino Nano pricing: Approximately $22 – $25
  • Arduino Micro pricing: Approximately $20 – $25

For either board, 3rd party clones can be purchased often for $10 or less.

In summary, the cost is essentially equivalent between both models when sourcing original Arduino or clone boards. Cost does not need to be a determining factor.

Usage Comparison

The Nano and Micro lend themselves to somewhat different use cases based on their size, design, and hardware differences:

Arduino Nano Typical Uses:

  • Basic microcontroller learning and experimentation
  • Physical computing projects with simple interfacing
  • Robotics applications not requiring USB
  • IOT sensor nodes using wireless communication

Arduino Micro Typical Uses:

  • Projects involving USB connectivity to PC or other devices
  • IOT end-nodes that require wired USB networking
  • Advanced or complex sensor systems
  • Tightly space constrained applications
  • Handheld control/monitoring with PC interface

Shared Applications:

  • Simple LEDs, buttons, motor control
  • Analog sensor readout and data logging
  • Low-speed human interface devices like game controllers

For projects with these basic embedded control needs, either Nano or Micro could suffice. The smaller form factor Micro may work better in tightly constrained spaces.

Summary Comparison

Arduino nano
ParameterArduino NanoArduino Micro
Digital I/O Pins2220
Analog In Pins812
Clock Speed16 MHz16 MHz
Flash Memory32 KB32 KB
Operating Voltage5-12V5-12V
USB SupportUART serialNative USB
Physical Size45 x 18 mm33 x 18 mm
Form FactorPCB BoardStamped module
Price Range$22 – $25$20 – $25


In summary, the Arduino Nano and Micro share similarities in their compact format and basic microcontroller capabilities. But key differences exist in their I/O configuration, physical design, and especially USB support that impact their use in various applications:

  • The Nano provides a compact, no-frills option for basic Arduino projects not requiring USB. Its rectangular PCB shape and standard pin layout offer versatility.
  • The Micro is best for advanced projects needing USB native connectivity to PC or other devices. Its tiny, stamped footprint can fit into the smallest spaces.

For projects that simply need a small Arduino board without USB or specificity on form factor, the lower cost Nano is likely the better choice. But for space-constrained applications requiring direct USB integration, the Micro’s advantages stand out. Understanding these tradeoffs allows selecting the right board for each project’s needs.

Frequently Asked Questions

Here are some common questions about the Arduino Nano and Micro:

Can shields be used with the Nano and Micro boards?

Yes, both Nano and Micro are compatible with standard Arduino Uno shields since they have the same operating voltage and I/O pin capabilities. However, the smaller physical size may block some shield attachments in compact layouts.

How difficult is transitioning code between the Nano and Micro?

The code can usually be adapted quite easily by changing pin numbers to match the different layouts. But sketches relying on UART serial functions will require changes to use the Micro’s USB capabilities instead.

How do you connect the Nano and Micro to a computer?

The Nano requires a separate USB-to-UART adapter, while the Micro provides built-in USB connectivity. Nano thus needs extra wiring and components to interface with USB.

Can the Nano or Micro be battery powered?

Yes, both boards can run on batteries or other standalone power supplies from 5-12V. Avoid exceeding 12V maximum input voltage to prevent damage. The Micro’s size can be advantageous for portable, battery-operated devices.

Which board is more beginner friendly?

For complete beginners, the Nano is likely easier to start with since its functionality matches the familiar Uno. After gaining experience, the Micro’s extra features become more useful. The Micro may seem more complex at first.


The Arduino Nano and Micro each have specialized strengths for different applications. Understanding their key hardware and software differences allows selecting the right board to best meet the needs of a particular microcontroller project. For basic low-cost Arduino projects, the Nano provides a compact solution. Where advanced processing and USB connectivity are required, the Micro is likely the superior choice.




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