Compress PDF — Reduce File Size Online
Reduce PDF file size while maintaining quality.
Drop your PDF file hereTap to select a file
Supports PDF, up to 200MB
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About Compress PDF
If you have ever tried to email a 40 MB scanned contract or upload a course handout to a portal that caps attachments at 10 MB, you already know why a PDF compressor is one of the most-searched browser tools on the web. Favtoo's Compress PDF tool shrinks the file in two ways at the same time: it re-encodes embedded images at a quality level you control, and it strips out the non-essential structural data — duplicate fonts, unused objects, thumbnail caches and viewer preferences — that bloats most exported PDFs without contributing anything to the rendered page.
Because the work happens entirely inside your browser tab using the open-source pdf-lib library plus an in-memory image re-encoder, the document is never uploaded to a server, never written to disk, and never visible to anyone but you. That matters for invoices, medical records, signed contracts, tax forms and anything else you would rather not hand to a third-party SaaS in exchange for "free" processing. When the tab closes, the file is gone from memory; nothing persists.
The compression ratio you see depends almost entirely on what the PDF contains. Text-only documents (a Word export, an OCR'd report) typically shrink by 10–25% because there is little image data to re-encode. Scanned PDFs and image-heavy decks routinely shrink by 60–80% at moderate quality settings, because most of the file size lives in the JPEG/JPX streams the compressor can re-render at a lower bitrate. If a particular file barely shrinks, that is usually a sign it was already optimised at export time — a common case for PDFs produced by export tools with a "Smallest File Size" preset.
A note on quality: PDF compression is lossy when images are involved. The default profile aims for the sweet spot where the page still looks crisp on a 1080p screen but the file is roughly 50% smaller. If you need archival quality, drop the compression level; if the document is going straight into an email and will be read once and discarded, the maximum setting is usually fine. You can always re-run with a different setting since the original file on your disk is never modified.
How it works
- 1Drop the PDF onto the upload area, or click to pick one from your device. Files up to 200 MB load instantly.
- 2Choose a compression profile. Recommended is balanced; choose Strong for the smallest size, or Light to preserve image fidelity.
- 3The compressor re-encodes embedded images, subsets fonts, and removes unused PDF objects in a single pass.
- 4Compare the before/after file size and download the result. Your original file on disk is never touched.
- 5If the size is still too large, run the output through the tool again at a stronger profile — there is no usage limit.
Common use cases
- Shrink a scanned contract from 30 MB to under 5 MB so it fits past an email gateway
- Compress a portfolio of design proofs before uploading to a client review portal
- Reduce the size of a research paper full of figures so it can be submitted to a journal that caps PDFs at 10 MB
- Trim a multi-page invoice export so it fits inside an accounting platform attachment limit
- Prepare a study packet of scanned chapters for sharing in a class group chat
- Cut a real-estate disclosure bundle down to fit a buyer’s mailbox quota
FAQ
How much can I compress my PDF?
Typically 40–70% size reduction depending on the content. PDFs with large embedded images see the biggest gains.
Does compression reduce quality?
Images are recompressed at a lower quality setting. Text and vector graphics remain perfectly sharp.
Is there a file size limit?
You can compress PDFs up to 200 MB. Processing happens entirely in your browser.
Will compressing the PDF make text blurry or hard to read?
Text inside a PDF is stored as vector glyphs, not as a raster image, so it is not affected by image compression at all. Only embedded photos, scanned pages, and figures are re-encoded. If your PDF was created by scanning paper documents, those scanned page images will lose a small amount of fine detail at higher compression levels — but normal reading-screen sharpness is preserved at the default setting.
How much smaller will my PDF actually get?
It depends entirely on what is inside. PDFs that are mostly text typically shrink by 10–25%. PDFs full of photos, screenshots, or scanned pages usually shrink by 50–80%. PDFs that were already optimised on export (e.g. an aggressive "Smallest File Size" preset, or a server-side optimiser) may barely shrink — that just means there is nothing left to remove.
Is it safe to compress confidential documents like contracts or medical records?
Yes. The entire compression process runs locally in your browser using the open-source pdf-lib and pdf.js libraries plus the browser’s built-in canvas image encoder. The file bytes never leave your device — there is no upload, no server-side processing, and no telemetry that includes your file. You can verify this by opening your browser’s network tab and watching the request log while you compress; you will see no POST requests carrying file data.
Can I compress a password-protected PDF?
Not directly. PDF passwords encrypt the file contents, so the compressor cannot read the streams it needs to re-encode. Use the Remove PDF Password tool first to unlock the file with the correct password, then compress the unlocked output, then re-protect it with Protect PDF if you need to.
Will OCR (searchable text) survive compression?
Yes. OCR text is stored as a separate, invisible text layer behind the page image. The compressor only re-encodes the visible image layer; the text layer is preserved untouched, so the output PDF stays fully searchable, copyable, and screen-reader-friendly.
Why does my compressed PDF look the same size as the original in some cases?
This happens when the input PDF was already heavily optimised, when it contains very little image data, or when it uses a custom font subset that pdf-lib cannot further reduce. If the compressor reports a 0–5% reduction, the file is essentially already at its minimum useful size and there is nothing more to remove without visibly degrading content.
Can I batch-compress multiple PDFs at once?
The current tool processes one PDF at a time by design — it keeps memory usage predictable on lower-end devices. To handle a folder, compress each file in turn; the tool stays open between runs and remembers your last-used settings.
Does compression remove form fields, annotations, or signatures?
No. Form fields, annotations (highlights, sticky notes, ink markup), bookmarks, and existing digital signatures are preserved through compression. Only redundant viewer data and embedded image streams are touched.