The Test
We use xz -9 as our baseline — it's widely regarded as the strongest general-purpose compressor available and the standard benchmark for maximum compression.
We took a 28GB Windows log file — 114.6 million lines — and ran it through xz at maximum compression, then through Smallest.zip.
Results
| Compressor | Size | vs xz -9 |
|---|---|---|
| xz -9 | 176.3 MB | baseline |
| Smallest.zip | 9.8 MB | -94.4% |
Smallest.zip compresses the Windows log to 9.8MB — that's 99.97% smaller than the original 28GB file, and 94.4% smaller than xz at maximum compression.
Key Takeaways
This is one of our most dramatic results yet. A 28GB file reduced to under 10MB — a 2,879:1 compression ratio from the original, and 18x smaller than what xz produces at maximum compression.
At 114.6 million lines, this is a massive log file. xz already does impressive work bringing it from 28GB to 176MB. Smallest.zip goes far beyond that, fitting the entire file into less than 10MB.
For organizations running Windows infrastructure at scale, log volumes like this are common across event logs, IIS logs, and system diagnostics. Compressing with Smallest.zip means storing 9.8MB instead of 176MB — a transformative reduction for long-term retention and compliance archiving.
Try It Yourself
Upload your own files at smallest.zip and see the difference. Every account starts with free credits.