If you’ve been dabbling in electronics or just starting your maker journey, you’ve probably come across the Arduino Nano R4 and the Arduino Uno R4. Both boards were big updates in 2023, and by 2025 they’ve cemented themselves as two of the most popular options for hobbyists, students, and even professional prototypes.
But here’s the question: Which one is right for you in 2025?
In this guide, I’ll break down the difference between Arduino Nano R4 and Arduino Uno R4. Whether you’re teaching kids, building robots, or working on IoT projects, by the end of this article you’ll know exactly which Arduino R4 board fits your needs.
What Makes the Arduino R4 Series Special?
Before comparing the Nano R4 and Uno R4, let’s set the stage. The R4 series introduced a game-changing upgrade:
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A 32-bit Renesas RA4M1 ARM Cortex-M4 processor (compared to the old 8-bit ATmega328P).
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More memory and higher clock speed, which means smoother performance for modern projects.
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Expanded I/O features like CAN bus and 12-bit ADC, which weren’t possible on older boards.
So essentially, both the Nano R4 and Uno R4 bring Arduino into 2025-ready territory. But they differ in size, power, and project fit. Let’s compare.
Arduino Nano R4 vs Arduino Uno R4 – Key Specifications
Here’s a side-by-side comparison to make things easier:
|
Feature |
Arduino Nano R4 |
Arduino Uno R4 |
|
Processor |
Renesas RA4M1, 48 MHz |
Renesas RA4M1, 48 MHz |
|
Flash Memory |
256 KB |
256 KB |
|
SRAM |
32 KB |
32 KB |
|
Size |
Tiny (45 x 18 mm) |
Classic (68.6 x 53.4 mm) |
|
USB |
USB-C |
USB-C |
|
Operating Voltage |
5V (compatible with most sensors) |
5V |
|
I/O Pins |
22 (20 digital, 8 analog) |
23 (14 digital, 8 analog, PWM support) |
|
Extra Features |
Built-in IMU (Nano R4 Sense model), RGB LED |
Onboard LED matrix (Uno R4 WiFi model) |
|
Best For |
Compact projects, wearables, IoT |
Beginners, classroom learning, prototyping |
Question 1: Which One is Easier for Beginners?
If you’re teaching STEM in schools or just starting out, the Arduino Uno R4 wins hands down.
Why?
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It’s larger and easier to plug jumper wires into.
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Most tutorials and textbooks still use the Uno pinout as the standard.
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It has built-in protections that make it harder to accidentally fry.
So if you’re buying your first Arduino in 2025, the Uno R4 will give you the smoothest learning experience.
Question 2: Which One is Better for Compact Projects?
If your project is all about saving space—like wearables, drones, or embedded sensors—the Arduino Nano R4 is your best friend.
At just 45mm x 18mm, it can fit where an Uno never could. And because it has nearly identical processing power, you don’t lose performance.
The Nano R4 Sense version even has a 9-axis IMU (accelerometer, gyroscope, magnetometer) and a built-in RGB LED. That means you can add motion sensing to your project without extra hardware.
Question 3: What About Power and Memory?
This is where both shine equally. With:
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256 KB of Flash memory (vs just 32 KB on the old R3 series).
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32 KB of SRAM.
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48 MHz clock speed.
Both boards can handle AI at the edge, IoT, and advanced robotics projects that were impossible on their predecessors.
So in terms of raw computing power, there’s no “better” option—they’re evenly matched.
Question 4: Which One is More Classroom-Friendly?
In Australian classrooms and makerspaces, the Uno R4 remains the go-to. Why?
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Teachers love its classic size—easy to pass around, easy to plug into breadboards.
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The Uno R4 WiFi version has a 5x5 LED matrix, which is perfect for teaching logic, animations, and text scrolling.
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It’s the board most STEM curricula are built on.
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Its compatible with previous generation UNO projects.
So if you’re buying for STEM DIY Kits for schools, the Uno R4 is still the default choice in 2025.
Question 5: How Do Costs Compare?
By 2025, pricing has stabilized in Australia:
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Arduino Nano R4: AUD $35–45
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Arduino Nano R4 Sense: AUD $55–65
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Arduino Uno R4 Minima: AUD $40–50
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Arduino Uno R4 WiFi: AUD $65–75
The Nano is cheaper, but once you add external sensors, the Uno’s WiFi version often ends up giving better value for money.
Question 6: Which One Should You Buy for IoT Projects?
If IoT is your focus, go Uno R4 WiFi.
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It comes with built-in ESP32-S3 WiFi/Bluetooth, so you don’t need extra modules.
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Great for smart home, weather stations, or connected robotics.
That said, the Nano R4 Sense is still amazing for IoT sensor nodes because of its tiny size and IMU. Many makers use Nanos as satellites and a Uno as the hub.
Question 7: Do They Work With Existing Shields and Accessories?
Yes, mostly.
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Uno R4 maintains the same shield compatibility as previous Unos. If you’ve got motor shields, relay boards, or display add-ons—they’ll likely still work.
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Nano R4 is compatible with Nano-format shields and breakout boards.
However, since they now run on a 32-bit ARM processor, some low-level libraries written for the 8-bit ATmega may need updates. Luckily, most major libraries have already been ported by 2025.
Question 8: Which One Should You Buy If You’re Already Using Arduino?
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If you already own older Unos and lots of shields, get the Uno R4 for smooth transition.
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If you’re a more advanced maker wanting to shrink your project footprint, go Nano R4.
Conclusion: Arduino Nano R4 vs Uno R4 in 2025
Both boards are excellent—you can’t go wrong with either. The choice depends entirely on your project needs:
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Buy the Arduino Uno R4 if:
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You’re a beginner.
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You’re teaching in classrooms.
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You need easy compatibility with shields.
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You want built-in WiFi.
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Buy the Arduino Nano R4 if:
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You’re working on compact or wearable projects.
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You want motion sensing out-of-the-box (Nano R4 Sense).
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You care about saving space and power.
By 2025, many makers actually keep both in their toolkit—because chances are, you’ll need each at some point.