Arduino Nano Every vs Classic Nano: Full Comparison

Choosing between the Arduino Nano Every vs Nano classic is a question that comes up constantly among makers upgrading their projects or buying their first compact Arduino board. The Nano Every was introduced as the successor to the classic Nano, but despite looking nearly identical and sharing the same footprint, these two boards have meaningful differences in processing power, memory, peripheral support, and compatibility. This full comparison will help you pick the right board for your specific project.

Table of Contents

• Quick Overview: Side-by-Side Summary
• Processor and Architecture
• Memory Comparison
• Peripherals and I/O
• Power Consumption
• Code and Hardware Compatibility
• When to Choose Which Board
• Frequently Asked Questions

Quick Overview: Side-by-Side Summary

Processor and Architecture

The most fundamental difference is the microcontroller. The classic Nano uses the ATmega328P — the same chip at the heart of the Arduino Uno, Pro Mini, and countless other boards. It is a mature, well-documented 8-bit AVR processor running at 16 MHz.

The Nano Every uses the ATmega4809, a newer member of the megaAVR 0-series introduced by Microchip Technology (after acquiring Atmel). It runs at 20 MHz, giving it a 25% speed advantage over the classic Nano. The megaAVR 0-series also introduces a new peripheral set: the Configurable Custom Logic (CCL), Event System, and 12-bit ADC — although Arduino’s abstraction layer does not expose all of these directly.

Importantly, the ATmega4809 does not use a bootloader stored in flash — it uses UPDI (Unified Program and Debug Interface) for programming, with a virtual COM port provided by the SAMD11 bridge chip. This means all 48 KB of flash is available for user code, unlike the Nano classic where the bootloader occupies 0.5 KB.

Memory Comparison

Memory is where the Nano Every wins decisively. The ATmega328P in the classic Nano has just 2 KB of SRAM — a constraint that becomes painful quickly when working with strings, large arrays, JSON parsing, or sensor buffers. The ATmega4809 triples this to 6 KB SRAM, which is a transformative improvement for real-world projects.

Flash Memory

The Nano Every offers 48 KB of user-accessible flash versus the classic Nano’s 31.5 KB (32 KB minus bootloader). This extra space is noticeable when using libraries like U8g2 (graphics), Ethernet, or complex state machines.

EEPROM

Interestingly, the classic Nano has more EEPROM: 1 KB versus just 256 bytes on the Nano Every. If your project relies on storing settings or calibration data in EEPROM, the classic Nano has an advantage here. That said, 256 bytes is sufficient for most configuration storage needs.

Practical Impact of More SRAM

Low SRAM is the most common cause of mysterious crashes and unpredictable behaviour in Arduino projects. When you run out of SRAM, the stack and heap collide — causing random resets, corrupted variables, and function calls returning garbage. The Nano Every’s 6 KB SRAM makes it substantially more reliable for complex code.

Peripherals and I/O

UART / Serial

Both boards have one hardware UART. On the classic Nano, Serial refers to the hardware UART on pins 0 and 1 and is also used for USB communication (through the FT232/CH340 bridge). On the Nano Every, Serial refers to the hardware UART (pins 0 and 1), while Serial (USB) is a separate virtual serial port through the SAMD11 bridge. This means Serial1 on the Every can be used for external serial communication without interfering with USB debugging.

SPI and I2C

Both boards support hardware SPI and I2C. The pin numbers are the same for I2C (A4/A5) but note that SPI pin mapping on the Nano Every uses pins 11 (MOSI), 12 (MISO), 13 (SCK) — same as the classic Nano, maintaining shield compatibility.

PWM

The classic Nano has 6 PWM pins (D3, D5, D6, D9, D10, D11). The Nano Every has 5 PWM pins. If your project depends on 6 simultaneous PWM outputs (rare in practice), the classic Nano wins.

Analog Inputs

Both boards offer 8 analog input channels (A0–A7). The classic Nano’s ADC is 10-bit (1024 steps). The ATmega4809’s ADC is also reported as 10-bit in the Arduino documentation, though the underlying hardware supports more resolution — Arduino’s analogRead() returns 0–1023 on both boards.

Power Consumption

Both boards operate at 5 V logic and draw similar active current at idle (approximately 19–20 mA). The Nano Every’s SAMD11 bridge chip draws a small additional quiescent current, but the difference is negligible in normal operation.

Neither board is particularly optimised for deep sleep operation compared to a bare ATmega328P standalone circuit — both have the voltage regulator and USB bridge drawing current. For battery-powered projects needing µA-level sleep currents, a bare ATmega328P or the Arduino Pro Mini with its LED and regulator removed is the better choice.

Code and Hardware Compatibility

This is the area most likely to catch you off guard. The Nano Every is mostly compatible with classic Nano code, but there are important exceptions:

Library Compatibility

Most popular Arduino libraries work on both boards. However, libraries that directly access ATmega328P registers (using TCCR0A, TCNT1, etc.) will break on the Nano Every since the ATmega4809 has a completely different register map and timer architecture. Examples include certain servo libraries, custom PWM libraries, and some tone generators.

Before choosing the Nano Every, check that all the libraries your project depends on support the megaAVR 0-series.

Interrupt Pin Differences

The classic Nano has dedicated external interrupt pins at D2 (INT0) and D3 (INT1) only. The Nano Every’s ATmega4809 supports pin-change interrupts on all pins, which is more flexible.

SoftwareSerial

SoftwareSerial on the ATmega4809 has known limitations — it is less reliable than on the ATmega328P. If your project uses SoftwareSerial for multiple serial devices, the classic Nano is safer.

Physical Compatibility

The Nano Every is pin-compatible with the classic Nano, meaning it fits in the same breadboard footprint and shield sockets. However, there is a subtle physical difference: the Nano Every is 0.1 mm taller due to the added component height from the SAMD11 chip on the back. Most shields accept this without issue, but check if your enclosure has tight clearances.

When to Choose Which Board

Choose the Arduino Nano Classic When:

• You need ATmega328P register-level compatibility (for specific libraries)
• You need 1 KB EEPROM for configuration storage
• You are using SoftwareSerial extensively
• You want the lowest cost (clone Nanos are widely available under ₹200)
• You are following a tutorial or course specifically written for the ATmega328P
• You plan to graduate to a custom standalone ATmega328P PCB

Choose the Arduino Nano Every When:

• Your project is running out of SRAM on the classic Nano
• You need to run more complex code with larger buffers or data structures
• You want more flash space for larger programs
• You want the higher 20 MHz clock for faster processing
• You use libraries that are already compatible with megaAVR 0-series
• You want a genuine Arduino board at a reasonable price

Frequently Asked Questions

Can I use Nano Every as a direct drop-in replacement for the Nano classic?

Physically and electrically, yes — the footprint is the same. Code that uses standard Arduino API functions (digitalWrite, analogRead, Serial, etc.) will work without modification. Code that uses direct ATmega328P register manipulation will require rewriting. Check all your library dependencies before switching.

Why does the Nano Every have less EEPROM than the classic Nano?

The ATmega4809 chip simply has 256 bytes of EEPROM by design. Microchip chose this specification for the megaAVR 0-series. If you need more persistent storage, consider using an external I2C EEPROM chip (e.g., AT24C256) which gives you 32 KB for a fraction of a rupee.

Is the Nano Every faster than the Nano classic?

In terms of raw clock speed, yes — 20 MHz vs 16 MHz, a 25% improvement. Both execute single-cycle instructions, so integer math and I/O operations are proportionally faster. For floating-point calculations, the speed difference is the same, as neither board has a hardware FPU.

Are clone Nano Every boards available?

The ATmega4809 is less commonly cloned than the ATmega328P, so you will find fewer unbranded Nano Every alternatives in the market. Most Nano Every boards available in India are genuine Arduino or very close equivalents, which is why the price point is higher than clone Nano classic boards.

Can the Nano Every run MicroPython?

No — MicroPython does not officially support the ATmega4809. For MicroPython on a Nano form factor board, consider the Arduino Nano RP2040 Connect or a Raspberry Pi Pico in Nano form factor.

Both the Arduino Nano Every and the classic Nano are excellent boards with distinct strengths. The classic Nano remains the most affordable and universally compatible choice, while the Nano Every delivers meaningfully better performance and memory headroom for more ambitious projects. For most new projects in 2024 where budget allows, the Nano Every is the smarter choice — its extra memory and speed will save you from the frustration of SRAM-related crashes as your code grows.

Shop All Arduino Nano Boards at Zbotic →