Compress PDFs without quality loss

What This Tool Does

The kittokit PDF Compressor reduces the file size of any PDF by targeting its largest component: embedded raster images. It re-encodes JPEG images at a lower quality setting and converts uncompressed bitmaps to space-efficient formats — all without touching text, vectors, or document structure.

Three compression levels let you balance quality against size reduction:

Level	Target use case	Typical size reduction
Low	Print-ready documents, legal filings	10–30%
Medium	Email attachments, web portals	40–60%
High	Preview copies, mobile viewing	60–80%

After compression, a side-by-side size comparison shows the original and resulting file sizes so you can decide whether to download or try a different level.

How It Works

PDF files store images as binary streams with optional compression filters. When a PDF is created from scans or image-heavy content, those streams are often uncompressed or encoded at maximum quality — far more data than most use cases require.

The compressor works in three passes:

1. Parse — the browser reads the PDF structure and identifies all embedded image XObjects.
2. Re-encode — each raster image is decoded, resampled if needed, and re-encoded at the selected quality level using the browser’s native canvas and image codec APIs.
3. Rebuild — the modified image streams are written back into the PDF structure; all non-image content (text, vectors, metadata, bookmarks) is copied unchanged.

Processing runs in a Web Worker to keep the browser UI responsive during large file operations.

What Are Common Use Cases?

Email attachments. Gmail, Outlook, and Yahoo Mail cap attachments at 25 MB. Scanned contracts and filled-in forms often exceed this limit; Medium compression typically brings them under the threshold.

Government and court filings. Many federal and state e-filing portals (PACER, state court systems) enforce strict file size limits, often 5–10 MB per document. Compressing before upload avoids rejected submissions.

Healthcare. US medical practices commonly send patient records via secure email or portal upload. Large radiology PDFs and multi-page forms compress well under High mode for quick transfer.

Real estate. Inspection reports, disclosure packets, and appraisal PDFs routinely reach 30–50 MB. Compressing them for Docusign, Dotloop, or email reduces upload time and storage costs.

Cloud storage. Google Drive and Dropbox free tiers fill up quickly with uncompressed PDFs from scanners. Batch-compressing files before saving frees significant space.

Academic submissions. Many university portals cap PDF uploads at 10 MB. Compressing a thesis or dissertation scan before submission prevents upload errors.

Frequently Asked Questions

Can I undo the compression? Once you download the compressed file, the original is unchanged on your device — the tool never modifies your source file. If the compressed result is unsatisfactory, simply try a lower compression level.

Will scanned handwriting still be legible? At Low and Medium levels, yes. High compression may blur thin pen strokes; use Medium for handwritten forms.

Does the tool support PDF/A files? PDF/A files use stricter compression rules. The tool can process them, but the output may no longer be fully PDF/A-compliant if image compression changes the color profile metadata.

What is the maximum supported file size? Because processing is local, the practical limit is browser memory — typically 200–300 MB on modern hardware. Very large files may take 30–60 seconds to process.