Adafruit Metro (Uno form factor), Metro Mini and Grand Central (Mega form factor) — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/adafruit-metro-grand-central/  (CC BY 4.0)
Basis: Adafruit CAD (MIT); Metro follows the Arduino Uno outline and hole pattern, Grand Central the Mega outline
Catalog version: 2026-10-20

Sizes: see table below
- Metro (328, M4, ESP32-S2, RP2350): 68.6 × 53.3 mm with the Uno's four holes (14.0/15.2 and 66.0 from the USB-end edge), USB at the left end, barrel jack beside it; shields fit.
- Grand Central M4: 101.5 × 53.3 mm, the Mega 2560 outline and holes. Metro Mini: 44.5 × 17.8 mm, breadboard-friendly, no holes.
- Metro boards use a micro-B or USB-C where the Uno has USB-B; the port position is the same, the cutout smaller.

product  bbox_l_mm  bbox_w_mm  bbox_h_mm
3382 Metro M4  71.9  53.3  14.5
2488 Adafruit Metro 328  71.1  53.3  12.1
2590 Metro Mini  43.8  17.8  4.3
4775 Metro ESP32-S2  71.9  54.6  16.9
6003 Metro RP2350  71.8  54.3  14.5
4064 Grand Central M4  104.9  53.4  14.5

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Adafruit (official): Adafruit_CAD_Parts: STEP, Fusion 360 and STL for Adafruit products — STEP, F3D, STL — MIT — https://github.com/adafruit/Adafruit_CAD_Parts

Free files (MIT License (Adafruit_CAD_Parts), Adafruit Industries; STEP + STL, 6 parts): https://xemstudio.com/files/adafruit/adafruit-metro-grand-central/index.json
API: https://xemstudio.com/api/geometry?object=adafruit-metro-grand-central