# Compress PDF > Compress PDF shrinks a PDF by redrawing every page as a JPEG image in your browser, so the file is never uploaded. Choose a quality preset or type a target size in KB or MB. Each file can be up to 100 MB. Text in the result is no longer selectable, and text-only PDFs may not get smaller. **Canonical:** https://trydocsy.com/pdf/compress **Last updated:** 2026-09-29 **Privacy:** Runs in your browser; the file is never uploaded. --- The compressor works on whole pages rather than on the objects inside the file. pdf.js draws each page onto a canvas, the canvas is saved as a JPEG, and pdf-lib places that JPEG on a new page of the same width and height. Whatever the original held, whether vector text, embedded fonts or high-resolution photos, each output page is a single picture, which is why scans and photo-heavy documents usually shrink a lot and why the result behaves like a scan. That approach has costs worth knowing before you upload the result anywhere. Selectable and searchable text, links, bookmarks and fillable form fields do not survive, and a PDF made mostly of typed text can come out the same size or even larger, because a picture of a page often weighs more than the instructions that drew it. Keep the original file for editing, and treat the compressed copy as the version you submit. ## How it works 1. **Add one or more PDFs** — Drop files on “Drop PDF files here” or click to browse; each file can be up to 100 MB. Several PDFs can go in together and are compressed one after another with the same settings. A password-protected file is set aside with a notice counting the skipped files. 2. **Pick Quality or Target Size** — The Settings panel has two tabs. Quality offers a Compression Level slider plus Max, High, Med and Low buttons, with Medium selected at first. Target Size takes a number with a KB or MB switch, and its quick buttons run from 50 KB to 10 MB. 3. **Press Compress and keep the tab open** — Each row shows a percentage while its pages are drawn. Leave the tab in the foreground: browsers slow background tabs so much that a file taking longer than 90 seconds is stopped with a timeout message. 4. **Check the row, then download** — A finished row lists the original size, the new size and the saving. If Target Size could not be met, an amber note under the file says so and gives the best size reached. Download saves each copy with “-compressed” added to its name. ## When you'd use it - **Email attachments over the limit** — When a mail provider bounces a large scan, Target Size with a value a little under the attachment cap produces a copy that goes through, while the original stays on your device untouched. - **Scanned application documents** — Phone-scanned certificates and ID proofs are already pictures of paper, so re-encoding them at a lower JPEG quality removes megabytes with little visible change. That suits portals that cap the size of each upload. - **Photo-heavy reports and brochures** — Documents built around camera photos carry far more image data than a screen needs. The Medium or High preset trims that for sharing in chat apps or linking from a website. - **A batch of files for one submission** — Adding every document at once applies the same setting to all of them, and the summary box totals the original and compressed sizes so you can check the bundle against a combined limit. ## How do the quality presets change the file? In Quality mode the slider sets two things at once. The JPEG quality follows the slider position (10 to 90, read as 0.10 to 0.90), and the drawing scale is 0.9 plus 0.8 times that value. Max (15) therefore renders pages at roughly 73 pixels per inch and Low (85) at roughly 114, with High (35) and Medium (60) in between at about 85 and 99. Those resolutions are comfortable for reading on a screen but low for print: small type and thin lines soften first, and on the Max setting JPEG blocking becomes visible around letters. Pick Low when a page has fine print that must stay legible, and Max when only the size limit matters. ## How does Target Size mode pick a quality? Target Size fixes the drawing scale at 1.4, about 101 pixels per inch, and binary-searches the JPEG quality between 0.05 and 0.92. Every pass re-renders the whole document, there are at most eight passes, and the search stops early once a result lands within 5% below the target. The file you get is the largest attempt that fitted, so it sits at or under the number you typed rather than exactly on it. When no pass fits, the tool makes one last attempt at the lowest quality and a smaller scale. If that is still too big, the file is kept but flagged “Could not reach target” with the best size in KB; drop pages with /pdf/delete-pages or break the document up with /pdf/split and try again. Asking for a size at or above the original shows a warning, and that output is rendered at high quality, so it can come out bigger than the file you started with. ## Why did my PDF get bigger or fail to compress? A PDF of typed text stores each page as a few kilobytes of drawing instructions and font data. Replacing that with a JPEG of the page can add weight rather than remove it, so a report exported from a word processor may show no saving or a negative one. For those files, cutting unneeded pages or exporting the source again with smaller images does more than this tool can. Password-protected PDFs cannot be opened and are skipped, so unlock them with /pdf/unlock first; a damaged file raises an error alert instead. A timeout almost always means the tab went into the background or the document is very long. Keep the tab visible, or compress the document in parts. ## Frequently asked questions **Q: Will my PDF text still be selectable after compressing?** A: No. Every page is saved as a JPEG image, so the compressed copy has no text layer: you cannot select, copy or search the words, and links and form fields are gone too. Run /pdf/ocr on the compressed file if you need searchable text again. **Q: Why is the result a little under my target rather than exactly on it?** A: The search keeps the largest file that fits under the number you entered and stops early once a fitting file is within 5% below it. JPEG sizes jump between quality steps, so hitting an exact byte count is not possible, and a result slightly under the target is what an upload limit needs anyway. **Q: Which PDFs shrink the most?** A: Scans and documents full of photographs, because their pages are already images and a lower JPEG quality removes a lot of data. Text-only PDFs shrink least and can even grow. **Q: Can I compress several PDFs in one go?** A: Yes. Add them together and they are compressed one after another with the same mode and setting. The summary box totals the sizes, and the Download button saves every finished copy. **Q: Why was my password-protected PDF skipped?** A: The compressor has to open and draw every page, which it cannot do without the password, so protected files are left out with a notice. Unlock the file with /pdf/unlock, then compress the unlocked copy. **Q: Is my PDF uploaded to a server?** A: No. pdf.js and pdf-lib run inside your browser tab, and the compressed copy is created there and saved straight to your device. **Q: What does “Compression timed out” mean?** A: Each file gets 90 seconds. Browsers throttle drawing in hidden tabs, so switching away mid-job is the usual cause. Keep the tab in front, or split a long document and compress the parts. ## Step-by-step guides using this tool - [How to Edit Text in a PDF for Free (and Why Most Editors Charge for It)](https://trydocsy.com/blog/edit-text-in-pdf-free) - [How to Make a Scanned PDF Searchable with OCR, Step by Step](https://trydocsy.com/blog/make-scanned-pdf-searchable) - [“File Is Too Large” When Uploading a PDF: Every Fix, in Order](https://trydocsy.com/blog/pdf-file-too-large-fixes) - [Merge Scanned Documents into One PDF Under 200 KB for an Application Portal](https://trydocsy.com/blog/merge-scanned-documents-pdf-under-200kb) - [Is Smallpdf Safe? Privacy, Cloud Servers, and Client-Side Alternatives](https://trydocsy.com/blog/is-smallpdf-safe) - [iLovePDF vs Smallpdf: Privacy, Free Limits, and Zero-Upload Alternatives](https://trydocsy.com/blog/ilovepdf-vs-smallpdf) ## Related tools - [Delete Pages from PDF](https://trydocsy.com/pdf/delete-pages) - [Split PDF](https://trydocsy.com/pdf/split) - [Unlock PDF](https://trydocsy.com/pdf/unlock) - [Grayscale PDF](https://trydocsy.com/pdf/grayscale) - [PDF to Image](https://trydocsy.com/convert/pdf-to-image) --- ## About TryDocsy TryDocsy is a free website of PDF, image and file-conversion tools that run entirely in your web browser, so your files are processed on your own device and never uploaded. It also includes photo and signature resizers preset to Indian government-exam specifications. - Website: https://trydocsy.com - Privacy Policy: https://trydocsy.com/privacy - Terms of Service: https://trydocsy.com/terms - Contact: https://trydocsy.com/contact