UPX: Rust Binary Size Optimization

By tweaking your build configuration and applying a post-build compressor, you can dramatically reduce the size of your Rust executables.

1. Default Release Build

With the default cargo build --release settings, the produced binary is about 6.1 MB.

$ cargo build --release
$ ls -lh target/release/your_binary
# -rwxr-xr-x  1 user  staff    6.1M Jul  3 20:00 your_binary

2. Optimized Release Profile

Add the following to your Cargo.toml to enable Link Time Optimization (LTO), strip symbols, and use a single codegen unit:

[profile.release]
debug = false
lto = true
strip = true
opt-level = 3
codegen-units = 1

Rebuild and check the size:

$ cargo build --release
$ ls -lh target/release/your_binary
# -rwxr-xr-x  1 user  staff    5.4M Jul  3 20:05 your_binary

This reduces the binary from 6.1 MB down to 5.4 MB.

3. Compression with UPX

For even smaller footprints, compress your Windows executable (or Linux ELF) with UPX:

$ upx ./target/release/your_binary.exe
                       Ultimate Packer for eXecutables
                          Copyright (C) 1996 - 2024
UPX 4.0.2       Markus Oberhumer, Laszlo Molnar & John Reiser   Jul 10th 2024

        File size         Ratio      Format      Name
   --------------------   ------   -----------   -----------
    5,400,000 ->   1,800,000   33.33%    win32/pe    your_binary.exe

Packed 1 file.

After UPX, the binary shrinks from 5.4 MB down to 1.8 MB.

---

Summary of sizes:

• Default (--release): 6.1 MB

• Tuned release profile: 5.4 MB

• + UPX compression: 1.8 MB

These simple steps can help you minimize the distribution size of your Rust applications.