free & open source · windows 10/11 · linux (experimental)
Little Big Mouse
Mix a 4K screen with a full-HD one and Windows loses the plot: your cursor leaves at eye level and lands somewhere near the desk. LBM makes it cross exactly where your screens actually meet.
Windows lines your monitors up by pixels. Your desk disagrees.
To Windows, every monitor is just a rectangle of pixels — a 27″ 4K panel and a 24″ full-HD one are nearly the same size. So when your cursor crosses from one to the other, it keeps its pixel row and jumps to a completely different physical height. Little Big Mouse maps your displays by theirreal dimensions instead, so crossings land where your eyes expect — and clicks and wheel scrolls right at the border follow along.
- Arrange screens by physical size and position, not pixel grids.
- One lightweight daemon does the routing; the app is just the control panel.
- Built for Windows 10/11 — with an experimental Linux port in the works.
What it does
One job — cursor crossings that feel right — plus the display tooling that grew around it.
Smooth crossings
The cursor crosses between screens of different DPI exactly where they meet — no jumps, no dead corners, clicks and scrolls land where you expect.
Game & app exclusions
Exclude a fullscreen or anti-cheat game and LBM steps aside — excluding an elevated app genuinely pauses the hook while it runs.
Border resistance
Draw sections along an edge, each with its own friction for plain moves and for drags — or an outright wall — so you stop flying into the next screen when you aim for a scrollbar at the edge.
Screen looping
Let the cursor wrap around — leave the rightmost screen and reappear on the leftmost, horizontally or vertically.
Color & brightness balancing
Control brightness and color profiles per display to even out mismatched panels — with an opt-in live read that follows OSD changes.
Display insights
Detailed information straight from your displays and drivers — makes, models, capabilities, adapters — handy for debugging weird setups.
See it in action
Two minutes, one cursor, zero jumps
TroubleChute walks through what LBM fixes and how to set it up — a very nice video, and a very big thanks to him.
The Linux port works, and currently builds from source. Mouse routing uses anevdev/uinput backend — it grabs the physical mice and drives a virtual pointer, exactly like the Windows hook — with Wayland-portal and X11 fallbacks.
- Developed and tested on KDE Plasma 6 (Wayland).
- One script builds the Rust daemon and the .NET UI and launches the app.
- Feedback from other desktops is very welcome on the issue tracker.
Docs & guides
Get it installed, set up your layout, and fix the weird cases.
Getting started
Install Little Big Mouse on Windows 10/11, arrange your screens the way they sit on your desk, and turn it on.
Using Little Big Mouse
A tour of the interface — layout, options, color and brightness balancing, and living with LBM day to day.
Border sections
Draw sections along a screen edge and give each one its own resistance for plain moves and for drags, or turn it into a wall.
Linux (experimental)
Run the experimental Linux port — install it from the AUR on Arch, or build from source elsewhere. evdev/uinput mouse routing, tested on KDE Plasma 6 Wayland.
Troubleshooting
The usual snags — the app won't start, the cursor won't cross, a game misbehaves — and how to report what's left.
Keep the cursor flying
Little Big Mouse is free and open source under GPL-3.0 — a nights-and-weekends project, not a product. If it fixed your setup or saved you a daily annoyance, a donation helps keep it maintained and improved.
Sponsor
