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Compress JXL to 100KB

Automatically compress any JXL image to 100KB or less.

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Maximum file size: 50 MB

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1 Select JXL
2 Compress JXL
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How to compress JXL

  1. Upload your JXL (up to 50 MB).
  2. The compressor automatically targets 100 KB or under.
  3. Download the compressed JXL — ready to use.

Quick fact about JXL

100 KB is a comfortable target for JXL — large enough to preserve quality on screen, small enough for fast delivery. The compressor prefers lossless mode when the source fits, otherwise iterates lossy quality.

Why compress JXL?

100 KB is the most common upload cap across the web. Because JXL is already efficient, hitting 100 KB is usually easy — the compressor can preserve high quality (or stay lossless) at 100 KB for small-to-medium images. This is useful for forms, marketplaces, and any system with a 100 KB limit.

Technical details

Input format JXL (JPEG XL)
Output format JXL
Target size 100 KB or under
Codec libjxl
Method Lossless first, then lossy iteration
Typical quality 80-90% at 100 KB
Transparency Preserved
Max file size 50 MB per file
File retention Auto-deleted after compression

How the conversion works

The compressor decodes the JXL and re-encodes it using libjxl. It first attempts lossless modular encoding; if the output exceeds 100 KB, it switches to lossy VarDCT and iteratively reduces quality until the target is met. At 100 KB, a JXL is typically 800-1200px wide with quality 80-90%.

When to compress JXL

Quality considerations

100 KB is comfortable for JXL — often achievable in lossless mode for small images, or lossy at 80-90% quality for larger ones. At 100 KB, the result is typically indistinguishable from the original on screens.

Limitations and caveats

Compatibility

Tips for best results

Compression levels explained

Level Size reduction Best for
Auto-target 100 KB Variable (until 100 KB) Web, forms, storage

Target a specific file size

Need to hit an exact size? Use our dedicated target-size tools:

Common problems and fixes

Output is still slightly over 100 KB
Crop or resize the image smaller first, or use the 500 KB variant.
Compression falls into lossy mode
Very large originals require lossy mode to hit 100 KB. For lossless results, use the 500 KB variant or the general JXL compressor.
Compression is slow
JXL encoding is CPU-intensive. Expect 3-5 seconds per image.

Frequently asked questions

How do I compress JXL to 100 KB? +
Upload your JXL — the compressor automatically targets 100 KB or under.
Will the JXL stay lossless at 100 KB? +
For small images, yes. Larger images may require lossy mode at 80-90% quality.
Does JXL compression to 100 KB lose quality? +
Only if lossy mode is needed. The compressor tries lossless first.
Is 100 KB enough for a JXL image? +
Yes — 100 KB is enough for sharp screen display at typical web dimensions.
Is transparency preserved? +
Yes — transparency is preserved.
Can I compress multiple JXLs at once? +
Yes — upload multiple files. Each is compressed independently.
Why is JXL compression slower? +
JXL uses advanced algorithms that take more CPU time but produce the smallest files.

Sources and references

Last reviewed: 2026-10-01