Free file compressor — PDF, JPG, PNG, WEBP
Every FileShrink compressor runs entirely in your browser. Drop a file, adjust quality if available, and download a lighter version of the same format. No upload, no signup, no watermark.
Compression is different from conversion. When you convert, you change the format: PNG becomes JPG, DOCX becomes PDF, the container changes. When you compress, you keep the same format but make the file lighter — either by re-encoding at a lower quality (lossy, like JPG and WEBP) or by optimizing the internal structure (lossless, like PDF object streams). The result is a smaller file that opens in the exact same tools as the original, looks nearly identical (or exactly identical in the lossless case), and is easier to email, upload, or store.
The tools below cover the four most common formats people need to compress. PDF compression re-serializes the document structure with object streams for a modest but honest reduction. JPG and WEBP compression re-encodes the image at a lower quality you choose with a slider. PNG compression re-encodes with the browser’s DEFLATE and strips metadata, with the honest caveat that gains are limited because PNG is already lossless. Everything runs client-side — your files never leave your device.
All compressors
Which compressor should you use?
Each format compresses differently. Here is what to expect from each tool and when to use it.
Compress PDF
Re-serializes the PDF’s internal structure with object stream compression. Gains are typically 10 to 30 percent — honest and lossless. The page content stays identical. Best for PDFs bloated by multiple edits, merges, or verbose export tools. For aggressive image-level compression, server-based tools are needed.
Compress JPG
Re-encodes the JPG at a lower quality via the Canvas API. A quality drop from 95 to 80 can cut file size by 50 to 70 percent with imperceptible loss on photographs. The quality slider gives you full control. EXIF metadata is stripped automatically.
Compress PNG
Re-encodes the PNG through Canvas, stripping metadata and re-applying DEFLATE. Gains are modest (0 to 20 percent) because PNG is already lossless and Canvas’s encoder is not state-of-the-art. For real size reduction, convert to WEBP instead.
Compress WEBP
Re-encodes the WEBP at a lower quality via Canvas. Same principle as JPG compression but with WEBP’s more efficient VP8-derived codec. Useful when a WEBP was exported at higher quality than the destination needs.
Quick decision guide
- Need a PDF under the email 25 MB limit?
- Use Compress PDF. A 10-30 percent structural reduction may push you under the cap without touching the content.
- Phone photos too large for a web page?
- Use Compress JPG at quality 80. Camera photos at quality 95 are overkill for screens — you can safely cut 50-70 percent.
- PNG screenshots taking too much space?
- Try Compress PNG first, but if the gains are small, convert to WEBP instead for dramatic savings.
- WEBP banner images slowing your site?
- Use Compress WEBP at quality 75-80. The quality drop is invisible on most photographs.
Why compress files in your browser?
Privacy by design
Your files stay on your device. No upload, no server, no third-party access — particularly important for confidential PDFs.
Instant results
No upload queue, no waiting on a server. Most compressions finish in under a second on a modern device.
Works offline
Once the page is loaded, compression keeps working without internet. Process sensitive files on a plane or in a restricted network.
Free forever
No per-file fee, no daily limit, no premium tier. Every compressor is fully functional for everyone.
Frequently asked questions
- What is the difference between compression and conversion?
- Compression reduces file size while keeping the same format (JPG in, smaller JPG out). Conversion changes the format (PNG in, JPG out). Both can reduce size, but compression preserves compatibility — the output opens in the same tools as the input.
- Is compression lossy or lossless?
- It depends on the format. JPG and WEBP compression is lossy — some quality is traded for size. PDF compression here is lossless (structure optimization only). PNG compression is lossless by definition, though gains are limited.
- Can I compress a file multiple times?
- You can, but each lossy re-encoding (JPG, WEBP) adds a small layer of quality loss. For lossless formats (PDF, PNG), re-compressing has no quality impact but also no additional gain.
- Why are PDF compression gains modest compared to Smallpdf?
- Server-based tools re-encode images inside the PDF at lower resolution, which produces 50-70 percent gains but degrades image quality. Our tool only optimizes the document structure, which is lossless. We are transparent about the trade-off.
- Are my files uploaded?
- No. Every compressor runs entirely in your browser. Files are read, processed, and returned locally. Nothing is ever uploaded, stored, or logged.