Compress JXL Without Losing Quality

1. Upload your JXL file (up to 50 MB).
2. Click 'Compress JXL Losslessly' — takes 5-15 seconds.
3. Download the smaller JXL — every pixel preserved.

JXL's modular mode is fully lossless — every pixel is preserved while still reducing file size by 20-30%. Perfect for archival masters where zero quality loss matters.

Sometimes every pixel matters — for archival masters, design source files, or work that may be edited later. JXL's modular mode is fully lossless: every pixel is preserved byte-identically while still reducing file size by 20-30%. This is a rare capability — most formats force you to choose between smaller files and lossless quality.

The compressor decodes the JXL image and re-encodes it using libjxl in lossless modular mode with maximum efficiency. Every pixel is preserved byte-identically. Only the encoding is more efficient.

• Archiving JXL masters with zero quality loss.
• Compressing JXL design source files.
• Preparing JXL for long-term archival.
• Reducing JXL library storage losslessly.
• Compressing JXL for storage systems with quotas.
• Optimizing JXL for backup without quality loss.
• Preserving maximum quality from JXL captures.

Lossless modular mode is byte-perfect — the decoded output is identical to the input. No quality loss whatsoever. Savings come from more efficient encoding, not quality reduction.

• Lossless mode is slower than lossy (5-15 seconds).
• Reduction is 20-30% (not as dramatic as lossy).
• For bigger reduction with some loss, use the general JXL compressor.
• Very small JXL files may not benefit significantly.
• HDR metadata preservation may vary.

• JXL opens in Firefox, Safari (via OS support), and some viewers.
• Native support in GIMP 2.10+, Krita 5+, Adobe via plugin.
• Windows 11 supports JXL with free extensions.
• Best for archival and storage optimization.
• Standard JXL — no special software for storage use.

• Lossless modular mode is byte-perfect — no quality lost.
• Savings are 20-30% — significant for archival.
• Slower than lossy mode (5-15 seconds).
• For bigger reduction, use the general JXL compressor (lossy).
• Batch-compress up to 50 MB at once.

Compression is slow

Lossless modular mode is CPU-intensive. Expect 5-15 seconds per image.

File is only 20-30% smaller

Lossless compression has limits. For bigger reduction, use the lossy JXL compressor.

Output doesn't open in some viewers

JXL support is limited (Chrome removed support in 2023). Use Firefox, Safari, or a JXL-compatible viewer.

• JPEG XL — Official Specification