Is it really possible to shrink a PDF with no quality loss?

Only partly. Repacking streams is lossless, but real size savings come from images, and re-encoding them as JPEG is lossy. This page uses a mild setting so the change is hard to see, but it is not zero.

What exactly is left untouched?

Text, fonts, vector graphics, links, bookmarks, page count and page size. Only embedded raster images are re-encoded.

Why did my PDF not get smaller?

It probably has few images or is already well compressed. The page then tells you the result is not smaller so you can keep the original.

How do I get an exact size instead?

Use the 100 KB, 200 KB, 500 KB or 1 MB pages, or type your own target in MB on the Compress PDF page. Stronger levels can show visible quality loss.

Reduce PDF Size, Keep Text Sharp

Reduce PDF File Size applies the mildest compression level: it repacks internal streams and re-encodes page images as JPEG at quality 75 with a 2000 px cap, leaving text, fonts and vector art unchanged. It shows how much the file shrank.

Drag and drop files here, or click to choose

Accepts PDF · up to 500.0 MB per file · up to 20 files at once

You can also paste a file with Ctrl/Cmd+V, or from the clipboard menu.

Target size in MB (optional)Leave empty for standard compression. Enter 1 to shrink the file to under 1 MB; the tool lowers image quality step by step until it fits.

Keep recent files in this browser (up to 5, 50.0 MB in total, never uploaded)

No setting that shrinks images is truly lossless, so this page uses the gentlest one. With no target size set, the tool repacks the PDF's internal streams, which changes nothing visible, and then re-encodes page images as JPEG at quality 75 with the longest side capped at 2000 px. Text, fonts, vector drawings, links and page size are never touched.

That mild level is usually invisible on screen and in normal print, and it removes the weight of oversized or poorly compressed photos. Savings depend on the document: a PDF full of photos can shrink a lot, while a text-only or already optimized file changes little. If the result is not smaller than the original, the page tells you to keep the original.

If you need a fixed size instead, use the target pages for 100 KB, 200 KB, 500 KB or 1 MB. They apply stronger levels when required, which trades visible quality for size.

Features

Mildest level only: JPEG quality 75, longest image side capped at 2000 px
Text, fonts, vector art, links and page size are never changed
Shows size before and after, and the quality used
Warns when the result is not smaller than the original
No account or watermark

When to use this tool

Lightening a report with photos before sharing it, while keeping print quality
Cleaning up a PDF exported with oversized images
Reducing storage for an archive of mostly-text documents with a few images

How do I reduce PDF size without losing quality?

Upload your PDF
Leave the target size empty to use the gentle default
Click Process
Check the size change and download the result

Limits and edge cases

JPEG recompression is lossy, so this is minimal loss rather than no loss
Files without large images, or already optimized, shrink little
Only JPEG and 8-bit RGB or gray images are re-encoded

Test results and conditions

Test file: a one-page PDF holding one 1400 × 1400 px noise-textured photo-like image, 5.1 MB. It is synthetic, so real photos will land differently. At the default level (JPEG quality 75, longest side 2000 px, no target) the result was 275 KB, about 95 percent smaller; the text and layout were unchanged.
A text-only or already-optimized PDF has no large images to re-encode, so it shrinks only by a few kilobytes.

Privacy for this tool

Files are uploaded over HTTPS, processed in memory or a short-lived temporary directory on our servers, and deleted when your result is ready. We do not keep copies for later browsing, training, or advertising profiles. See the Privacy Policy for retention details and AdSense cookie disclosures.

Frequently asked questions

Is it really possible to shrink a PDF with no quality loss?: Only partly. Repacking streams is lossless, but real size savings come from images, and re-encoding them as JPEG is lossy. This page uses a mild setting so the change is hard to see, but it is not zero.
What exactly is left untouched?: Text, fonts, vector graphics, links, bookmarks, page count and page size. Only embedded raster images are re-encoded.
Why did my PDF not get smaller?: It probably has few images or is already well compressed. The page then tells you the result is not smaller so you can keep the original.
How do I get an exact size instead?: Use the 100 KB, 200 KB, 500 KB or 1 MB pages, or type your own target in MB on the Compress PDF page. Stronger levels can show visible quality loss.

Last updated: 2026-10-18

More ways to use Compress

Compress PDF to 100 KB - Set the target to 100 KB and let the tool try stronger image settings until it fits.
Compress PDF to 200 KB - Set the target to 200 KB and let the tool try stronger image settings until it fits.
Compress PDF to 500 KB - Set the target to 500 KB and let the tool try stronger image settings until it fits.
Compress PDF to 1 MB - Set the target to 1 MB and let the tool try stronger image settings until it fits.
Compress PDF to 2 MB - Set the target to 2 MB and let the tool try stronger image settings until it fits.
Compress PDF for Email - Size a PDF for an email attachment limit; the target is preset to 10 MB.
Compress PDF to 5 MB - Aim for 5 MB: the target is already filled with 5.

Call this from code

Every tool on this site is a plain REST endpoint - no account or API key needed for anonymous use. Built for AI agents and developers as much as for browsers.

curl -X POST "https://pdf123.xyz/api/v1/misc/compress-pdf" \
  -F "[email protected]" \
  -o output.pdf

Also available as an MCP tool for agent clients that speak Model Context Protocol (JSON-RPC 2.0 over POST /mcp). Full API reference

Use it from an AI agent

Skill

Claude Code, Codex, Cursor and other AI agents can run Compress for you with this skill: /skills/pdf123-compress.md

All agent skills

Files are used only for this processing job and deleted automatically afterward.