21700 lithium cell — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/21700-cell/  (CC BY 4.0)
Basis: industry standard; nominal values
Catalog version: 2026-10-20

Overall (mm): length 70, width 21, height 21
- Nominal Ø21 × 70 mm; real cells about Ø21.1–21.4 and 70.0–70.5 mm.
- Not interchangeable with 18650 holders.

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: List of battery sizes — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/List_of_battery_sizes

Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/21700-cell/index.json
API: https://xemstudio.com/api/geometry?object=21700-cell