⚙️ Compression Settings
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Upload your PDF, choose a compression level, and download a smaller file in seconds. Built for 2026 with modern browser engines — perfect for email, cloud uploads, archives, and sharing on any device.
Upload your PDF below, pick the compression strength, then click Compress PDF. Your smaller file will be ready in moments.
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Upload a PDF above, then click Compress PDF to reduce file size
These are the principles that guided the design of this tool — and the things you should look for in any PDF compressor you use in 2026.
Your file is parsed, re-rendered and saved entirely in your browser using JavaScript — not on a remote server.
Three preset levels plus separate image-quality and resolution sliders so you can target exactly the right output.
You see the original size, the compressed size, the percentage saved and the page count — no hidden marketing fluff.
No email signup, no daily quotas, no watermarks, no "upgrade to download" pop-ups — ever. Just compress and go.
A clean PDF compressor built for speed, simple controls, and easy downloads on desktop and mobile. Designed to work with modern browsers and the latest PDF rendering engines.
prefers-color-scheme.A quick workflow designed for speed, sharing, and storage savings.
For the curious: a step-by-step look at exactly what the tool does between the moment you drop your file and the moment your compressed PDF downloads.
When you drop a PDF, the browser hands the file to JavaScript as a Blob. The bytes never touch the network — they exist only in your tab's memory.
Mozilla's PDF.js library opens the file, decodes its internal object tree, and exposes each page as a renderable object with width, height, fonts, and image data.
The tool creates an offscreen HTML5 canvas sized by your chosen Render Resolution multiplier, then asks PDF.js to draw the page onto it pixel-by-pixel.
The canvas is converted to a JPEG string using canvas.toDataURL('image/jpeg', quality). This is where the bulk of the size reduction happens.
Each JPEG page is added to a fresh, lean PDF using the jsPDF library, with A4 portrait dimensions and aspect-preserving scaling so nothing gets stretched.
The finished PDF is exported as a Blob, given a temporary Object URL, and offered to you via a download link. Nothing is uploaded; the file goes straight from memory to your disk.
A short, plain-language guide to how PDFs store data and why they often grow much larger than they need to be.
A PDF — short for Portable Document Format — is a container file that can hold text, vector graphics, raster images, fonts, forms, annotations, attachments, and metadata. It was originally created by Adobe in 1993 and later standardized as an open ISO specification. The current core standard is ISO 32000-2, also known as PDF 2.0, maintained by the International Organization for Standardization. You can read the official overview on the ISO 32000-2 standard page.
Because PDFs can hold so many different kinds of data, their file size can vary enormously. A 10-page text-only contract may be only 80 KB, while a single page of high-resolution scanned color images can balloon to 20 MB or more.
In most large PDFs, the file size is dominated by embedded images — especially when documents are scanned from paper at 300 DPI or higher, or when they contain screenshots, photos, signatures, or marketing visuals. Other size contributors include embedded fonts, unused page objects, layered annotations, and metadata.
This is why PDF compression rarely changes plain-text contracts very much, but can dramatically shrink scanned reports, image-heavy brochures, and visually rich presentations.
PDF compressors typically combine two strategies. Lossless compression removes redundant data without changing the visual content — for example, by stripping unused objects, optimizing object streams, or applying Flate/Deflate compression to text and vectors. Lossy compression reduces image quality and resolution to save space, similar to how JPEG works. You can learn more about JPEG and other image compression formats on the MDN Web Docs image formats reference.
This tool focuses on image-based optimization: each page is re-rendered at a chosen resolution and re-encoded as a JPEG inside a fresh, compressed PDF. That approach delivers the biggest size savings on scanned and image-heavy documents, which is exactly the type of file that most people struggle to share.
Lossless compression is reversible — you can rebuild the exact original bytes from the compressed data. ZIP files, PNG images, and Flate-encoded PDF streams all use lossless techniques. The trade-off is that lossless compression has a hard mathematical limit; you can only squeeze so much out of truly random data.
Lossy compression is one-way. It discards information your eyes are unlikely to notice — fine color gradients, very high-frequency noise, tiny shading differences. JPEG is the classic example, and it's why a 10 MB scan can become a 1 MB file that still looks "fine" to most readers. Once you save a lossy version, you can't recover the discarded detail, which is why we always recommend keeping the original.
A condensed timeline of how PDF compression evolved from a niche prepress concern into a daily-life utility for billions of people.
A practical guide to picking the right level depending on the type of PDF you have and where you plan to share it.
| Level | Image Quality | Render Resolution | Best For | Typical Savings* |
|---|---|---|---|---|
| Light | 92% (high) | 1.6× (sharp) | Print-quality PDFs, legal documents, portfolios you want crisp | 10 – 30% |
| Medium | 78% (balanced) | 1.25× (balanced) | Everyday sharing, email attachments, cloud uploads | 30 – 60% |
| Strong | 58% (smaller) | 1.0× (compact) | Quick previews, web forms, low-bandwidth sharing | 50 – 85% |
*Savings vary based on the content of your PDF. Text-only documents save less; scanned or image-heavy PDFs save more.
PDF compression solves real, everyday problems. Here are the most common situations where shrinking a file makes life easier.
Most email providers cap attachments around 20–25 MB. Compressing a scanned report often gets it under the limit in one step.
Gmail limits attachments to 25 MB and Outlook to about 20 MB on free tiers. A compressed PDF avoids the "upload to cloud" fallback.
Many employer portals and university applications restrict PDF resumes and transcripts to 2 MB, 5 MB, or 10 MB.
Tax filings, visa applications, and licensing portals frequently reject PDFs that exceed strict size limits.
Compressed invoices and receipts are easier to attach to accounting software like QuickBooks, Xero, or FreshBooks.
Journals, conference systems, and university LMS platforms often impose tight per-file limits for thesis chapters and assignments.
Messaging apps cap PDF file size (WhatsApp around 2 GB, Telegram around 2 GB), but smaller files send and download much faster.
Free tiers of Google Drive, Dropbox, OneDrive, and iCloud fill up fast. Compressed PDFs help you stay under the cap longer.
Smaller files use less mobile data when sending PDFs over 4G/5G connections, which still matters in 2026 for travelers and rural users.
Online print services often have size caps. A compressed file uploads faster and is easier to preview before printing.
Hosting PDFs on a website? Smaller files load faster, improve user experience, and help with Core Web Vitals scores.
If you keep years of scanned receipts, contracts, or medical records, compressed PDFs save gigabytes of cumulative storage.
Court e-filing systems often cap exhibit PDFs at 25 MB or even 10 MB per document. Compression is mandatory for big evidence files.
Hospital portals and patient apps sometimes limit imaging report uploads. A compressed PDF gets through where the original was rejected.
Mortgage portals and listing platforms ask for compact disclosure PDFs, inspection reports, and floor plans for fast loading.
Embassy portals frequently cap supporting-document PDFs at 1–2 MB and reject anything larger without explanation.
Self-publishers and educators distributing PDF books benefit from smaller files that download quickly on slow networks.
Freelancers and agencies send proofs, mockups, and final deliverables. Compressed PDFs preview faster in client email clients.
Why compression matters in 2026: a snapshot of the size limits imposed by common platforms. Numbers reflect typical free-tier values and can change over time.
| Service | Attachment / Upload Limit | Workaround Built In? | Why Compression Helps |
|---|---|---|---|
| Gmail | ~25 MB per email | Yes (Drive link) | Avoids the awkward "saved to Drive" fallback |
| Outlook.com | ~20 MB per email | Yes (OneDrive) | Keeps the attachment inline, no extra clicks |
| iCloud Mail | ~20 MB per email | Yes (Mail Drop) | Keeps everything in the body of the email |
| Yahoo Mail | ~25 MB per email | No | Hard rejection if you exceed it |
| ~2 GB per document | No | Smaller files send and download faster on cellular | |
| Telegram | ~2 GB per document (4 GB Premium) | No | Slow on weak networks; compression helps |
| Slack (free) | ~1 GB total team storage | Limited | Compression saves shared team quota |
| Google Drive (free) | 15 GB total account | No | Shared with Gmail; every MB counts |
| Dropbox (free) | 2 GB total account | No | Tiny quota — compression is essential |
| OneDrive (free) | 5 GB total account | No | Compressed PDFs stretch the free tier |
| iCloud Drive (free) | 5 GB total account | No | Photo-heavy; PDFs compete with images |
| WeTransfer (free) | ~2 GB per transfer | No | Compressed files upload faster |
| Government e-filing | Often 5–25 MB per doc | No | Many portals silently reject oversized files |
| University LMS | Often 10–50 MB per submission | No | Critical when deadline is in minutes |
The single biggest factor in PDF size is the scanner DPI you start with. Picking the right setting can be more effective than any compressor.
| DPI Setting | Color Mode | Typical Size (1 page A4) | Use For |
|---|---|---|---|
| 72 DPI | Black & white | ~30 KB | Quick reference, throwaway scans |
| 150 DPI | Grayscale | ~80 KB | On-screen reading, email forwarding |
| 200 DPI | Grayscale | ~150 KB | Searchable office documents |
| 300 DPI | Color | ~600 KB | Standard quality — official documents |
| 400 DPI | Color | ~1.2 MB | Photographs, archival originals |
| 600 DPI | Color | ~2.8 MB | Print reproduction, fine-art scanning |
| 1200 DPI | Color | ~11 MB | Rarely needed outside archival imaging |
Small habits that make a noticeable difference in how much smaller (and how readable) your compressed PDFs turn out.
Medium is the safest default for nearly every PDF. Only go Strong when size matters more than visual polish.
Scanned documents, photo-rich brochures, and screenshot-heavy PDFs see the biggest savings — often 60% or more.
A purely textual PDF is already very compact. Expect smaller percentage savings on contracts, ebooks, or plain reports.
Files meant for on-screen reading don't need high render resolution. Reserve high resolution for documents that will be printed.
If a scanned PDF is huge, sometimes it's better to re-scan at 150 DPI grayscale rather than compress a 600 DPI color scan aggressively.
Compression is one-way for image-heavy PDFs. Save the original copy somewhere safe before sharing the compressed version.
Use a meaningful output name like "invoice-2026-04-compressed.pdf" so you can tell originals and compressed copies apart later.
Open the compressed PDF and check important details — small text, fine lines, signatures — to make sure they're still readable.
If the first pass didn't shrink enough, go back to the original file and try a stronger level. Don't compress an already compressed file.
If your PDF is still too large, consider splitting it into smaller chapters and compressing each one separately for finer control.
If color isn't necessary, converting a scan to grayscale before compression can cut file size by another 30–60% with no quality penalty for the reader.
White space around scanned pages is still data. Cropping tight margins in your scanner software before saving can save a surprising amount.
Many scanners auto-detect blank pages — turn that on. A 50-page PDF with 8 blanks removed is noticeably smaller and easier to read.
Sending a PDF to someone on mobile data abroad? Be more aggressive. Sending to a designer for review? Stay light.
Before compressing 200 archived scans, run one test file through the tool to confirm the settings give you the size and quality you need.
Approximate file sizes for common document types, plus typical savings after medium compression. Your results will vary depending on content, fonts, and how the original PDF was created.
| Document Type | Typical Original | After Medium | Approx. Savings | Notes |
|---|---|---|---|---|
| 1-page text contract | 80 KB | 70 KB | ~10% | Already lean — small savings expected |
| 10-page text report | 400 KB | 320 KB | ~20% | Some font/image cleanup |
| 20-page scanned report (color) | 12 MB | 3.5 MB | ~70% | Big savings on scanned images |
| 50-page scanned book chapter | 45 MB | 9 MB | ~80% | Excellent compression target |
| Photo portfolio (15 pages) | 28 MB | 7 MB | ~75% | Use Light for portfolio quality |
| Resume / CV (2 pages) | 500 KB | 250 KB | ~50% | Great for job portals with 1 MB cap |
| Slide deck export (30 slides) | 18 MB | 4 MB | ~77% | Images compress well |
| Invoice with logo | 1.2 MB | 300 KB | ~75% | Strong logo / signature compression |
| Lecture slides w/ photos | 22 MB | 5 MB | ~77% | Photos dominate the size |
| Magazine PDF (40 pages) | 55 MB | 14 MB | ~75% | Use Light if quality matters |
| Architecture floor plan | 8 MB | 6.5 MB | ~20% | Vector lines — keep Light |
| Medical imaging report | 35 MB | 9 MB | ~75% | Confirm legibility of fine print |
Built and tested for modern browsers. Compression relies on three standard APIs — the File API, Canvas, and Blob — that are available everywhere mainstream browsers ship today.
| Browser | Minimum Version | Performance | Notes |
|---|---|---|---|
| Google Chrome | 100+ | Excellent | Fastest canvas rendering and JPEG encoding |
| Microsoft Edge | 100+ | Excellent | Same engine as Chrome; identical performance |
| Mozilla Firefox | 100+ | Excellent | Native PDF.js integration; very stable |
| Safari (macOS) | 15+ | Excellent | Hardware-accelerated canvas on Apple Silicon |
| Safari (iOS / iPadOS) | 15+ | Good | Watch memory on very large PDFs |
| Brave | 1.40+ | Excellent | Built on Chromium; same as Chrome |
| Arc | 1.0+ | Excellent | Modern Chromium build, no quirks |
| Opera | 85+ | Excellent | Chromium-based, full compatibility |
| Vivaldi | 5.0+ | Excellent | Same engine; very predictable |
| Samsung Internet | 20+ | Good | Works well on flagship phones |
| Internet Explorer | any | Not supported | Retired by Microsoft in 2022 |
Transparency matters. Here's exactly what happens when you use this PDF compressor.
This tool uses client-side JavaScript libraries — PDF.js by Mozilla for parsing and jsPDF for rebuilding the PDF — both of which run entirely inside your browser tab. Your PDF is read from your device, rendered to in-memory canvases, re-encoded, and then offered back to you as a download.
That means the tool itself never needs to upload your file to a server in order to compress it. Compression speed depends entirely on your device's CPU and available memory, not on a remote service.
Although the compressor logic is local, modern websites do receive normal browser metadata such as your IP address, user agent, and referrer. If you're working with sensitive material — medical records, legal contracts, financial documents — it's always smart to verify how a tool behaves. You can open your browser's developer tools and inspect the Network tab while compressing to confirm no PDF data is being sent externally.
For background reading on browser security and safe document handling, see the Electronic Frontier Foundation's privacy resources and the National Cybersecurity Alliance.
When you close the browser tab, the PDF data held in memory is discarded automatically. There's no account, no cloud storage, no history. If you want a copy of your compressed file, save the download to your device before closing the tab.
Don't take our word for it. Press F12 (or Cmd+Option+I on Mac) to open developer tools, switch to the Network tab, then drop a PDF and run compression. You'll see the page's own assets loading, but no outbound request carrying your PDF bytes. That's the difference between a server-side and a client-side tool — and it's auditable in seconds.
A lot of folklore swirls around PDF compression. Here are the most common myths and what's actually true.
Light compression is often visually indistinguishable from the original. The visible difference only shows up at aggressive settings or with very small text in scanned images.
Compressing an already-compressed file rarely shrinks it further and often adds artifacts. Always start from the original document.
Some optimize image streams, some strip metadata, some re-render pages, some do all three. The technique chosen matters more than the brand name.
Many large PDFs are bloated by uncropped scans, embedded fonts you don't need, and duplicate images — not by extra useful detail.
Some online tools upload files to servers, but modern browser-based ones — like this one — process everything locally. You can verify it in DevTools.
Acrobat is powerful, but free tools using open-source libraries can deliver comparable or better results for the most common compression tasks.
Small text-based PDFs sometimes still contain embedded font subsets you don't need or unused metadata that can be stripped further.
Image-based compression can make selectable text become flat images. If you need a searchable result, run OCR after compression — it isn't broken, it just needs a second pass.
Sometimes a different approach reduces file size more effectively. Here's a quick comparison.
| Approach | What It Does | Quality Impact | Best When |
|---|---|---|---|
| PDF Compression | Re-encodes images and structures at lower quality | Some quality loss possible | You have a final PDF and need it smaller fast |
| Re-scanning at lower DPI | Captures the paper at 150 DPI instead of 600 DPI | Cleaner than aggressive compression | You still have access to the original paper |
| Splitting the PDF | Divides one big PDF into smaller files | No quality loss | You only need part of the document |
| Converting to PDF/A | Archive-friendly format with embedded resources | May increase file size | Long-term legal archiving — see ISO 19005 |
| Exporting from source | Re-export from Word/Pages/Docs with lower image settings | Best quality at small size | You still have the original source file |
| Cloud share link | Upload once to Drive/Dropbox, share the URL | No file change | Recipient is okay opening a link |
| ZIP archive | Adds zip compression around the PDF | Minimal — PDFs already compress internally | Sending many small PDFs together |
| Convert images to grayscale | Strips color channels before compressing | Loses color, gains 30–60% size reduction | Color is irrelevant to the document |
| OCR + re-export | Runs text recognition, then exports text-based PDF | Vastly smaller for scanned docs | Bulk-archiving scanned paperwork |
If your results don't look the way you expected, one of these issues is usually the cause.
The most common reason is that the PDF was already optimized — many PDFs exported from Word, Pages, or Google Docs are quite efficient, and image-based compression can't shave much off a text-first document. Try a stronger level, or check whether the original is mostly vector text.
This happens when render resolution is too low. Page text is being converted to images at a smaller scale than the original. Re-run with the Light preset, or pick High Resolution from the resolution dropdown. For best text clarity, especially for printing, use 1.6× resolution.
Make sure the file you uploaded is a real PDF and not a renamed image or document. Some PDFs are password-protected — you'll need to remove the password first using your original PDF software before compressing. Adobe's Acrobat Help Center has guides for unlocking PDFs you own.
This tool standardizes pages into A4 portrait while preserving aspect ratio with a small margin. PDFs that originally used unusual page sizes (legal, A3, custom) will be re-fitted. If you need exact original page sizes, use a tool that supports per-page geometry preservation.
Compression speed depends on your device. PDFs with hundreds of pages or extremely high-resolution scans can take a minute or more on older laptops or budget phones. Close other tabs, avoid running the compressor on huge files over a weak mobile connection, and let your device handle one PDF at a time.
That's expected for this kind of image-based compression: each page is rendered as a JPEG, so the text becomes part of an image rather than a text layer. If searchability matters, keep the original around or run OCR on the compressed file afterward using a separate tool.
Browsers cap how much memory a single tab can use. PDFs over 500 MB or with hundreds of high-resolution pages can occasionally push past that. Close other tabs, restart the browser, and try Medium or Strong instead of Light to keep memory usage down.
PDF compression isn't a niche concern — it's a daily routine in many professions. Here's how different industries lean on it.
Law firms compress trial exhibits, deposition transcripts, and contracts to fit court e-filing portals and email caps.
Hospitals and clinics compress radiology reports, intake forms, and patient documentation for fast sharing between providers.
Teachers compress lecture handouts, students compress dissertations and lab reports, libraries shrink digitized archives.
Auditors and accountants share compressed statements, ledgers, and supporting documentation with clients securely.
Designers share compressed floor plans, RFIs, and submittal packets that would otherwise overflow vendor portals.
Editors and journalists compress proofs, layouts, and press kits to email reviewers without blowing past inbox limits.
Online sellers compress product catalogs, return forms, and shipping labels for faster customer downloads.
Agencies compress public-record PDFs for portal hosting and to meet strict accessibility-and-performance mandates.
Agents send compressed disclosures, comp reports, and signed contracts to clients across phone and email channels.
Researchers compress preprints, datasets-as-PDF, and journal submissions to satisfy publisher upload limits.
Engineers compress technical drawings, datasheets, and inspection reports for fast distribution to field teams.
Travel professionals compress itineraries and travel docs that need to be readable offline on a phone with low storage.
Curated links to authoritative documentation and standards bodies if you want to go deeper into PDF technology, accessibility, and security.
Short, friendly definitions for the technical terms you'll see when working with PDFs.
Everything you need to know about reducing PDF file size in 2026.