Free Compress PDF Online

Compress PDF files to reduce their size while maintaining quality. Perfect for email attachments and uploads.

Last updated May 8, 2026

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Almost every government portal, university application system, recruitment site, and email gateway enforces a strict PDF size limit — 1 MB, 2 MB, sometimes 5 MB — and the PDF you actually need to upload is usually somewhere between 8 MB and 25 MB. The classic example: a scanned passport with attached bank statements that comes out at 14 MB, while the visa portal demands under 2 MB. Our free online PDF compressor solves exactly that. Drop the PDF in, pick one of three compression levels (Low for documents that need to stay print-quality, Medium for everyday email-friendly compression, High for maximum size reduction when you have a hard upload cap to hit), and download the smaller version. The compressor uses pdf-lib internally with three layered optimisations: object stream compression (rewriting redundant PDF object structures into compact streams), unused-object pruning (removing orphaned references that bloat older PDFs), and optional metadata stripping (clearing the title/author/keyword fields that add nothing to the visible content). For PDFs heavy with embedded images (the most common bloat source), High compression also recompresses image streams at lower quality for additional savings. Typical compression results: a 15 MB scanned-passport PDF drops to around 4–5 MB at Low setting, 2–3 MB at Medium, and 800 KB to 1.5 MB at High — usually enough to clear most upload caps. Text-heavy PDFs (contracts, reports without images) compress less aggressively because they are already efficient; expect 10–25% reduction. Image-heavy PDFs (scanned documents, photo-rich brochures, multi-page receipts) compress dramatically — 50–80% reduction is normal at High setting. Common workflows people use it for: shrinking visa application bundles before uploading to embassy portals, fitting CV and degree-certificate PDFs under the 2 MB cap on Indian government recruitment portals (UPSC, SSC, IBPS), reducing court filing PDFs to fit e-filing system limits, compressing scanned bank statements before emailing to accountants or loan officers, and trimming bulky e-book or research-paper PDFs for easier WhatsApp/email sharing. Everything runs in your browser using pdf-lib — your PDFs never travel to any server, never get logged, never get cached anywhere outside your device. After compression, you can [add a password](/tools/pdf-password) for security, [add a watermark](/tools/pdf-watermark) for confidentiality marking, or [merge with other compressed PDFs](/tools/pdf-merger) into a single submission file. For source images that you want to compress before they end up in a PDF, use our [Image Compressor](/tools/image-compressor) — compressing input images first often produces dramatically smaller PDFs in the next step.

How to Use Compress PDF

Upload Your PDF

Drag and drop your PDF file into the upload area or click to browse. The tool reads the file size and page count, displaying both before compression so you can see what you are starting with.

Choose Compression Level

Select Low (best quality, modest size reduction — good for print-bound documents), Medium (balanced — the default for email and most uploads), or High (smallest file — best for hitting strict portal upload caps).

Compress & Download

Click "Compress PDF" and the optimisation runs in your browser using pdf-lib. The compressed file is offered for download with the exact size reduction percentage shown in real time.

Features

Three Compression Levels

Choose between Low (~10–25% reduction, print-quality preserved), Medium (~30–50% reduction, balanced for everyday use), and High (~60–80% reduction, maximum compression for strict upload caps).

Size Comparison

See original and compressed file sizes side by side with the exact reduction percentage. Useful when targeting a specific size cap (under 2 MB, under 1 MB, etc.).

Metadata Stripping

High compression removes metadata (title, author, keywords, creation date, software signature) for additional size reduction and a privacy benefit — the PDF will not reveal what software or device created it.

Object Stream Optimisation

Compresses redundant PDF object structures into compact object streams, the same technique Adobe Acrobat uses for its "Reduced Size PDF" export.

Image Re-Compression

On High setting, embedded JPEG images are recompressed at lower quality. The most aggressive reductions come from image-heavy PDFs (scans, photo-rich brochures) where image data dominates total size.

Browser-Based & Private

All compression happens in your browser using pdf-lib. Your PDFs are never uploaded to any server, never logged, and discarded the moment you close the tab. Useful for confidential contracts, payslips, medical records, and ID scans.

Benefits of Using Compress PDF

Completely Free

Use Compress PDF without any cost, limits, or hidden fees. No premium plans needed.

No Installation

Works directly in your browser. No software downloads or plugins required.

100% Private

Your files and data are processed locally. Nothing is uploaded to external servers.

Works Everywhere

Compatible with Chrome, Firefox, Safari, Edge on desktop, tablet, and mobile.

No Sign-Up

Start using the tool immediately. No account creation or email verification.

Always Available

Access this tool 24/7 from anywhere in the world, on any device.

Frequently Asked Questions

Yes, completely free with no limits on file size, number of compressions per day, or sign-up requirements. The tool runs in your browser so there is no server cost on our side that would require usage limits. No watermarks are added to compressed output.

Highly dependent on the source PDF type. Image-heavy PDFs (scanned documents, multi-page receipts, photo-rich brochures) typically reduce by 50–80% at High setting because images dominate total size. Text-heavy PDFs (contracts, reports without images) reduce by 10–25% because text streams are already compact. As a rule of thumb: a 15 MB scanned-passport bundle drops to under 2 MB at High, and a 5 MB text-only contract drops to around 4 MB.

Low and Medium compression preserve quality — the optimisations (object stream rewriting, unused-object pruning) are lossless and visible quality is identical to the original. High compression also recompresses embedded JPEG images at lower quality, which is where some quality loss can appear in image-rich PDFs (mild JPEG artefacts in solid-colour areas like sky or skin). For text and vector graphics, even High compression is visually lossless.

No hard limit because processing runs in your browser, but practical performance depends on your device memory. Most modern desktop browsers handle PDFs up to 200 MB comfortably. For files larger than 500 MB, expect significant slowdown because the entire PDF has to be loaded into browser memory. On mobile devices, the practical ceiling is around 100 MB.

No. The entire compressor runs in your browser using pdf-lib (a JavaScript PDF library). Your file is loaded into the browser tab, processed locally, and the compressed output is generated on your device. Nothing travels over the network — useful for confidential PDFs like signed contracts, salary slips, bank statements, medical records, and ID documents.

Start with Medium compression and check the result size. If it is still above the cap, switch to High compression. If High is still too large, the PDF probably has very high-resolution embedded images — extract them first using the [PDF Splitter](/tools/pdf-splitter) (one page per file), compress the images with our [Image Compressor](/tools/image-compressor), and reassemble using the [PDF Merger](/tools/pdf-merger). This two-stage process can hit very aggressive caps that single-pass compression cannot.

Most likely your PDF contains very high-resolution scanned images (300 DPI or higher) or embedded fonts that account for most of the file size. Text-heavy PDFs are already efficient and have little fat to trim. For maximum reduction on a stubborn PDF: try High compression, accept the metadata stripping, and consider whether the visual quality at High is acceptable for your use case. If not, the source images need to be downsampled first via the two-stage process above.

Form fields and their values are preserved across all compression levels. Digital signatures are technically preserved as data, but compression alters the underlying PDF byte structure, which means the signature's cryptographic check may flag the document as "modified after signing" — this is true for any PDF compression tool, including Adobe Acrobat's built-in compressor. For digitally-signed legal documents, sign AFTER compression rather than compressing a signed PDF.