Visual Data Size
by TM_DE
Visual Data Size shows the exact serialized byte size of an item's nested data in its inventory tooltip, Fabric client-side only.
What it does
The mod reports how large an item's stored data is, counting bytes and tag entries, including items inside containers such as shulker boxes. Sizes are shown in B, KiB and MiB, and the figures update as soon as an item's data changes, so a stack can be measured again after an edit. The information appears in a dark-gray line matching the vanilla advanced tooltip.
Only the client needs the mod, so it works on a single-player world or on a multiplayer server without any server-side installation. Fabric API is required, and Mod Menu is optional for opening its settings. Files are published for Fabric only, for game versions 26.2 and 26.3, with 1.3.1 for 26.3 as the latest file from 2026-09-27. The mod is released under All rights reserved and is not open source, although its source code and issue tracker are public.
Key features
Exact data measurement
Serialized item data is measured in bytes and shown in B, KiB or MiB, so the size of a stack is read directly.
Nested tag counting
Tags stored inside an item are counted, including custom data on filled shulker boxes, books and modded items.
Container contents included
Items held in containers are added to the total, which helps when inspecting boxes that hold many stacks.
Live in-game commands
Display can be toggled and size formats changed from chat with tab-completed client commands, and the visualdatasize command configures the mod.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 1
Optional 1
Use cases
Who it’s for: Mod developers, server administrators and technically minded players who want to see how item data is stored. Players who only play vanilla content will see little difference from the regular tooltip.
How it compares
Storage Tracker is a client-side only Fabric mod under the MIT License, published for 26.1.2 – 26.3, and it tracks storage rather than item data size. Shulker-In-Shulker is a Fabric mod for client and server, under the CC0 1.0 Universal license, covering 1.21.6 – 26.3, which changes how shulker boxes can be nested. OmniChest is client-side only, open source under CC0 1.0 Universal, and published for 1.21.10 – 26.2.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Visual Data Size | Fabric | 26.2 – 26.3 | Client-side only | 2026-09-27 |
| Storage Tracker | Fabric | 26.1.2 – 26.3 | Client-side only | 2026-10-02 |
| Shulker-In-Shulker | Fabric | 1.21.6 – 26.3 | Client and server | 2026-10-10 |
| OmniChest | Fabric | 1.21.10 – 26.2 | Client-side only | 2026-08-11 |
Questions
Does Visual Data Size need Fabric API?
Does the server need Visual Data Size installed?
Why does the size change after an item is edited?
Which game versions does Visual Data Size support?
In the catalog
Visual Data Size is one of 8,499 Technology mods on ModsFinder, and one of 4,201 Technology mods for Fabric. 8,071 mods support Minecraft 26.3.
Similar mods
What the author says
Visual Data Size is a lightweight, purely client-side diagnostic tool for Minecraft 26.3. It makes the serialized data size and internal structure of items visible directly in your inventory tooltips. Whether you are a mod developer checking item data, a server administrator investigating large item structures, or…
Official listing
- Modrinth page
- modrinth.com/mod/visual-data-size
- Owner
- TM_DE
- Published
- 2026-07-14
- Updated on Modrinth
- 2026-09-27
- Facts verified
- 2026-10-15