Adafruit SGP40 air quality sensor (#4829, STEMMA QT): 25.4 × 17.78 mm board and 4 mounting holes — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/adafruit-sgp40-4829/  (sheet CC BY 4.0)
Basis: Adafruit's EagleCAD board file for the SGP40 STEMMA QT breakout, with connector height from the JST SH datasheet.
Catalog version: 2026-10-20

Overall (mm): length 25.4, width 17.78, height 4.55
- Board 25.40 × 17.78 with R2.54 corners, centred, board bottom at 0. Board thickness 1.6 is assumed (Adafruit's board file does not state it); everything else is from the board file.
- Four plated Ø2.5 mounting holes at (±10.16, ±6.35) from the board centre: a 20.32 × 12.70 rectangle.
- Two STEMMA QT (JST SH 4-pin) connectors on the short edges, openings facing outward; 4.55 overall height.
- Not modelled: the loose 1×5 0.1 in header along one long edge and the 2.44 × 2.44 SGP40 sensor; leave the sensor open to air.
- All dimensions are exact nominal millimetres, true size, with no tolerance added.

hole  x (mm)  y (mm)  diameter (mm)
1  -10.16  -6.35  2.5
2  +10.16  -6.35  2.5
3  -10.16  +6.35  2.5
4  +10.16  +6.35  2.5

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Adafruit: Adafruit SGP40 Air Quality Sensor Breakout - STEMMA QT (#4829) — web — Publisher's page; dimensions are facts — https://www.adafruit.com/product/4829
- Adafruit: Adafruit-SGP40-PCB repository — web — Publisher's page; dimensions are facts — https://github.com/adafruit/Adafruit-SGP40-PCB
- Adafruit Learning System: Adafruit SGP40 Air Quality Sensor guide — web — Publisher's page; dimensions are facts — https://learn.adafruit.com/adafruit-sgp40
- JST: SH connector series datasheet — web — Publisher's page; dimensions are facts — https://www.jst-mfg.com/product/pdf/eng/eSH.pdf

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/adafruit-sgp40-4829/index.json
API: https://xemstudio.com/api/geometry?object=adafruit-sgp40-4829