Chat Calc
by Rime
With Chat Calc, typing a math expression into the chat box shows its result before the message is sent, and the mod runs on the client alone.
What it does
Chat Calc is a Fabric port brought up to the newest Minecraft releases after the original went without updates for a long time. The code was rewritten from Java to Kotlin, and the feature set stays close to the original, so the original mod's description still applies to most behavior.
The mod needs Fabric API and Fabric Language Kotlin. RimeLib is bundled inside the mod file, so it does not have to be installed separately. Chat Calc is client-side only, so players install it on their own game and servers do not need it. Files are published for Fabric for 13 release versions, and the latest file is 4.2.5 for 1.21.10, released 2025-10-15. The code is open source under the Mozilla Public License 2.0, and the source and issue tracker are public.
Key features
Inline calculation in chat
Math typed into the chat field is evaluated, and the result appears as the player types it.
Ported to newer releases
The port covers versions the original no longer supports, across the newest releases through 1.21.10.
Kotlin codebase
The mod was converted from Java to Kotlin, so its code uses the Kotlin language and its runtime library.
Bundled library
RimeLib is included inside the mod file and does not need a separate install.
Compatibility
Latest build for each game version and loader.
1.21.x11 of 11 versions with builds
1.20.x2 of 2 versions with builds
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 2
Embedded 1
Use cases
Quick sums while playing
A player can check a crafting ratio or a coordinate offset without leaving the game or opening an outside calculator.
Who it’s for: Players on Fabric who want quick arithmetic inside the chat field. Servers do not need the mod, so it works on any server a player joins.
How it compares
Calculator commands is a Fabric mod for 1.20.2 – 1.20.4, licensed under the MIT License and open source, with a client-side only environment. Yet Another Calculator is open source under the Apache License 2.0, supports Fabric and Quilt, and covers 1.20 – 1.21.7. QuickCalc targets 1.16.5 – 1.18 and is open source under the GNU Lesser General Public License v3.0 only. Chat Calc is the only one of these that runs on 1.21.8 and newer releases.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Chat Calc | Fabric | 1.20.5 – 1.21.10 | Client-side only | 2025-10-15 |
| Calculator commands | Fabric | 1.20.2 – 1.20.4 | Client-side only | 2024-01-20 |
| Yet Another Calculator | Fabric and Quilt | 1.20 – 1.21.7 | Client-side only | 2025-07-08 |
| QuickCalc | Fabric | 1.16.5 – 1.18 | Client-side only | 2021-12-05 |
Questions
Does Chat Calc need Fabric Language Kotlin?
Does a server need Chat Calc installed?
Which game versions have Chat Calc files?
In the catalog
Chat Calc is one of 36,990 Utility mods on ModsFinder, and one of 25,772 Utility mods for Fabric. 15,569 mods support Minecraft 1.21.10.
More from Rime
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What the author says
This is a port of ChatCalc by RTTV (which is also a port of ChatCalc by Kokeria) to the newest minecraft versions, because it hasn't been updated in a long time. It's also completely converted from Java to Kotlin, just because I can. The functionality hasn't changed much, so you can check the original mod's…
Official listing
- Modrinth page
- modrinth.com/mod/chat-calc-kt
- Owner
- Rime
- Published
- 2024-05-16
- Updated on Modrinth
- 2025-10-15
- Facts verified
- 2026-10-15