Compress PDF Online Free - Reduce File Size Without Losing Quality | PDFCrush

Reduce PDF size by up to 85% free - no software, no sign-up, nothing uploaded to any server. Compress scanned PDFs, resumes, or large documents in under 30 seconds. Works on Android and iPhone.

You attach the PDF. Hit send. The error appears: file too large.

Or you get to the government portal upload screen and find a 5 MB limit - and your scanned form is 22 MB. Or the HR application system rejects your resume because it's 12 MB when they cap uploads at 2 MB.

These are not edge cases. This happens to most people who regularly deal with documents. The good news: the fix takes 30 seconds, costs nothing, and requires no software.

Why Does a Simple PDF End Up So Large?

The size of a PDF tells you exactly how it was made.

Scanned documents

When you scan a page - or photograph it with your phone - each page is stored as a full-resolution image. A single A4 page at 300 DPI in colour is 2-5 MB. A 10-page scanned contract can easily hit 25 MB, even though most of that resolution is wasted on white space the reader will never examine closely.

Design-exported PDFs

Files from Canva, InDesign, Figma, or PowerPoint default to print settings: 300 DPI, full colour profile, embedded fonts, and sometimes editing layers. The printer needs all of this. The person reading it on their phone does not.

Embedded photos and diagrams

A single high-resolution product photo can add 3-5 MB to a Word or Google Docs export. If a report has ten images, that alone can push the file to 30-50 MB.

Hidden metadata

PDFs carry editing history, document thumbnails, font copies, and authoring tool data - none of which is visible to the reader, but all of it adds weight to the file.

Scanned documents are the biggest compression opportunity. A 20 MB scanned contract often compresses to 3-5 MB with no visible quality difference.

How to Compress a PDF Online - Step by Step

No installation. No account. Your file never leaves your device.

1. Open the Compress PDF tool in your browser.
2. Drag and drop your PDF onto the page, or click to browse and select it.
3. Choose a compression level: Low, Balanced, or Maximum.
4. Click Compress PDF. Processing runs locally in your browser.
5. Download your compressed file. The tool shows the original size, compressed size, and exact percentage saved.

Most files are done in under 30 seconds.

Which Compression Level Should You Use?

This is where most people go wrong - defaulting to Maximum when Balanced would do, or using Low when they actually need Maximum. The right choice depends on what the PDF contains and where it's going.

Low - preserve quality, moderate size reduction

Reduces file size 20-40%. The document looks identical to the original at any zoom level. Use Low when:

• The PDF will be printed or professionally archived
• You're sending to a designer or printer who will repurpose the images
• Visual sharpness of diagrams or photos is the priority over file size

Balanced - right for most situations

Reduces size 40-60%. Text stays perfectly sharp (it's stored as vectors, not pixels). Images look clean and professional at normal reading size. Use Balanced for:

• Contracts, proposals, and client-facing business documents
• Reports with charts, branded visuals, or product imagery
• Any file where you want a significantly smaller size without visible compromise

Maximum - when the size limit is the priority

Reduces size 60-85%. Images soften slightly at very close zoom, but are indistinguishable from the original at standard reading distance. Text is completely unaffected at every compression level - it's mathematical data, not an image. Use Maximum for:

• Email attachments (Gmail caps at 25 MB, but many corporate servers cap at 5-10 MB)
• Government portal and HR system uploads
• WhatsApp, Telegram, or mobile sharing
• Scanned invoices, receipts, and identity documents
• Any document where readability is the goal, not print quality

For contracts, invoices, and text-heavy documents: Maximum compression is genuinely undetectable at normal reading size. Text in PDFs is never affected by image compression - it's stored as vector data that compression doesn't touch.

When no compression level is enough

If Maximum compression still doesn't reach your target size, split the PDF first. Use the Split PDF tool to divide it into sections, compress each separately, then merge if needed. For scanned documents that are still too large after compression, check the scan resolution - rescanning at 150 DPI instead of 300 DPI halves the base file size before compression even runs.

Compressing Scanned PDFs

Scanned PDFs and software-generated PDFs are fundamentally different things - and that difference is why scanned documents have so much more to gain from compression.

A regular PDF exported from Word or Google Docs stores text as text: the font, character shapes, and positions are mathematical data that takes almost no space. A 20-page Word document exports to a few hundred kilobytes.

A scanned PDF works differently. Every page is a photograph. A two-page scanned invoice can be 8 MB. A 10-page greyscale office document can be 25 MB. Not because the content is complex, but because a photo of white paper with black text is still a photo.

What to realistically expect

Best settings for scanned files

Always use Maximum compression for scans. There's no meaningful trade-off. The softness effect of Maximum compression is calibrated to what's visible at 100% zoom on screen - and a scanned page at Maximum is indistinguishable from the original at any distance you'd actually read it.

If you're scanning specifically to create a small shareable file, scan in greyscale at 150 DPI. Greyscale scans compress significantly better than colour, and 150 DPI is more than enough for any document that will only be read on screen or attached to an email.

Make scanned PDFs searchable after compressing

Compression reduces file size - it doesn't add a text layer. If you need to copy, search, or extract text from the document, run it through OCR PDF after compressing. OCR adds a full text layer without changing anything visually.

Compress PDF for Email

Email attachment limits are more restrictive than most people expect:

The practical safe target for any email attachment is under 5 MB. Under 2 MB is better - it opens instantly on mobile, arrives reliably on any connection, and clears every corporate mail policy without friction.

Contracts and business documents: Use Balanced. Text stays crisp, images look professional.

Scanned invoices, receipts, and forms: Use Maximum. It's already a photo of paper - aggressive compression changes almost nothing the recipient will notice.

Design-heavy files with important imagery: Use Balanced or Low if visual quality genuinely matters to the recipient.

If Maximum compression still leaves you above the limit, use the Split PDF tool to break the document into sections, compress each, and send as separate attachments. For very large documents where splitting feels awkward, compress and share via Google Drive or Dropbox instead.

Compressing PDFs for WhatsApp and messaging apps

WhatsApp passes PDFs through without re-compressing them (unlike photos). Large files are slow to arrive, eat mobile data, and sometimes fail to open on low-end phones. For anything over 3 MB, compress before sending. A 15 MB scanned document typically compresses to 2-3 MB - the difference between instant delivery and making someone wait.

Compress Resume PDF

Resumes look simple, but they can be surprisingly heavy depending on how they were created.

A one-page Canva resume is commonly 8-15 MB. The reason: design tools export at 300 DPI with embedded fonts, custom assets, and colour profiles optimised for print. HR portals cap uploads at 2-5 MB. LinkedIn's PDF upload limit is 5 MB. An 8 MB resume fails silently - it either gets rejected outright, or an ATS system flags it before a recruiter ever sees it.

What size to target

Under 1 MB is the practical ideal - fast to upload, no risk of hitting any portal limit, and opens instantly on any device. A 10 MB Canva resume almost always compresses under 1 MB with no visible quality loss. The recipient sees the same design - just without the print-quality overhead.

Which settings to use

Use Balanced compression for resumes. This reduces size 40-60% while keeping text crisp and design elements clean at normal viewing size.

If Balanced still leaves you above the portal limit, switch to Maximum. For a resume, the image softening at Maximum is genuinely undetectable in practice - what matters is that your name, contact details, and professional information are legible, and text in PDFs is always stored as vectors that compression never touches.

After downloading, open the compressed file and zoom to 100%. If everything reads clearly, you're done.

Keep the compressed version of your resume on hand. Recompress whenever you update content. A large resume being auto-rejected by an ATS before a recruiter reads it is an entirely preventable problem.

Compressing to a Specific Target Size

Different systems have different limits. Here's what to expect and what to do:

Under 100 KB - Very small. Realistic only for short, clean, text-only documents. For scanned pages or anything with images, this is rarely achievable without visible degradation. Use Maximum compression and, if needed, use Split PDF to isolate just the critical pages.

Under 200 KB or 500 KB - Achievable for 1-3 page documents. Most scanned invoices and single-page ID documents compress from 2-5 MB down to 150-400 KB on Maximum.

Under 1 MB - Achievable for most documents up to 5-8 pages on Maximum. A 10 MB scanned form typically lands below 1 MB.

Under 2 MB - The most common target. Most 5-15 page documents (contracts, reports, multi-page forms) reach this on Balanced or Maximum.

Under 5 MB - For multi-page scans and design exports currently at 20-40 MB: Maximum compression typically brings these well under 5 MB. If not, split first, compress each section, then optionally merge.

What Compression Actually Does

Most compression tools take the blunt approach: re-render every page as a low-quality image. That uniformly degrades the document - text pages that didn't need any quality reduction suffer alongside image-heavy pages that did.

A better approach analyses each page separately before changing anything:

• Pages that are mostly text are compressed losslessly - the font data and layout are mathematically preserved with no quality change
• Image-heavy and scanned pages get targeted optimisation at the quality level you selected
• Greyscale content (most office documents, invoices, forms) is handled with greyscale-specific compression rather than being processed as colour
• Metadata, editing history, embedded thumbnails, and redundant font copies are stripped from the file entirely

The result is a document that looks the same at normal reading distance but is significantly smaller - because compression was applied where it actually made a difference, and left alone where it didn't.

Compressing a PDF on Your Phone

You don't need a laptop. The tool works identically in a mobile browser.

On Android

Open Chrome, go to the Compress PDF tool, tap to upload from Files or Google Drive, choose a compression level, and download. The compressed file saves to your Downloads folder. The whole process takes under a minute.

On iPhone

Open Safari or Chrome, visit the tool, tap to select from Files or iCloud Drive. After compression, save the result to your Files app. Works on any iPhone running iOS 14 or later.

Most phone document scans - whether from the built-in camera scanner or apps like Adobe Scan - produce files at camera resolution by default. That's efficient for print, wasteful for sharing. Compressing immediately after scanning keeps sizes manageable before you forward anything.

What to Do After Compressing

Make a scanned PDF searchable: Compression reduces the file size but the content is still stored as images - you can't select or search the text. Run the file through OCR PDF to add a full text layer.

Combine multiple documents: If you've compressed several related files separately, Merge PDF combines them into one.

Split before compressing very large files: Documents with 100+ pages often compress more efficiently in sections. Split PDF divides by page range; compress each part, then merge if needed.

Protect before sharing: If the document is sensitive - a contract, financial statement, or identity document - add a password before sending.

Online Compression vs Desktop Software

For occasional to regular compression - a few files per week - a browser-based tool is faster, free, and more private than any subscription. Desktop software only makes sense for professional workflows processing dozens of files daily, where granular control over individual images or elements is worth the monthly cost.

Most people who think they need Acrobat for PDF compression don't. The browser-based workflow handles every common use case without installation, accounts, or payment.