Compress PDF
Make a big PDF small enough to email, upload or store — without turning it to mush.
Drop your file hereTap to add your file
or click to choose · sent securely, deleted right after
Private by design. Your file is sent over an encrypted connection, processed in an isolated sandbox with no internet access, then deleted the instant it’s done. We never store it or read it. How this works
A PDF gets heavy for one main reason: the pictures inside it. Scans, screenshots and high-resolution photos carry far more data than the text around them. Compress PDF shrinks a file by re-encoding those images at a sensible resolution and stripping out redundant data and leftover metadata — so the document still reads exactly the same, but weighs a fraction of what it did.
You stay in control of the trade-off. Choose a gentle squeeze to keep every detail crisp, or push harder when you just need the file to fit under an email or upload limit. Most image-heavy PDFs come down by 50–80%; text-only PDFs are already compact, so expect a smaller change there. Everything runs free, with no sign-up and no watermark.
How it works
Compression mostly works on the images in your PDF. Ream downsamples them to a screen-friendly resolution, re-encodes them efficiently, and clears out duplicated objects and hidden metadata. Vector text and shapes are already tiny, so they are left sharp and untouched.
Why some PDFs barely shrink: if your document is mostly selectable text, there simply isn’t much to squeeze — it’s already efficient. The big savings come from scans, exported presentations and photo-rich reports. If a file won’t go small enough, try the Strong level, or convert colour scans to grayscale first.
How to Compress PDF
Add your PDF
Drag your file onto the page or click to choose it. One PDF at a time, up to 50 MB.
Choose a compression level
Recommended balances size and sharpness for everyday files. Strong squeezes hardest — ideal for scanned or image-heavy documents. Light keeps the most detail when quality matters most.
Compress & download
We optimise the images and remove redundant data, then hand you the smaller PDF. Your upload is processed in an isolated sandbox and deleted the moment it is done.
Compression levels compared
Ream gives you three honest levels instead of a single black-box button. Here is what each one does and when to reach for it:
| Level | What it does | Typical size drop | Best for |
|---|---|---|---|
| Recommended | Balanced image downsampling (~150 dpi), strips metadata | 40–70% | Everyday documents that mix text and images |
| Strong | Aggressive downsampling (~72 dpi), maximum squeeze | 60–90% | Scans and photo-heavy files, or hitting tight limits |
| Light | Gentle optimisation (~300 dpi), keeps fine detail | 20–50% | Files you will print, or where sharpness matters |
Not sure? Start with Recommended. If the file is still too big, run it again on Strong.
Compress a PDF to a target size (100 KB, 500 KB, 1 MB)
Lots of forms and inboxes demand a specific ceiling — “max 2 MB”, “under 500 KB”, sometimes even 100 KB. There is no magic slider that guarantees an exact number, because the result depends on what is inside your PDF, but here is how to get there reliably:
- Under 1–2 MB: most files reach this on Recommended. Scans may need Strong.
- Under 500 KB: use Strong. Realistic for short documents and single-page scans.
- Under 100 KB: achievable for text-light, few-page documents. For big colour scans, also convert to grayscale and remove pages you don’t need.
Compress, check the size, and if you’re still over the limit, step up a level or trim the document — you’ll get as close to the target as the content allows without wrecking readability.
What makes a PDF large
Knowing where the weight sits helps you shrink smarter:
- Scanned pages & photos — by far the biggest factor; each page is a full-resolution image.
- High-resolution images at 300 dpi or more, when 96–150 dpi is plenty for screens.
- Embedded fonts and duplicated objects that were never de-duplicated.
- Leftover metadata, revision history and hidden layers from the app that made the file.
Compress tackles all of these — it re-encodes images, removes duplicates and clears metadata in one pass.
When to compress a PDF
- Email attachments — slip under the usual 10–25 MB mailbox limits so your message actually sends.
- Upload forms with strict caps — job applications, visa and government portals, tax and finance uploads that reject anything too large.
- Faster sharing and web pages — smaller files open quicker and use less bandwidth.
- Saving storage — keep archives lean in the cloud or on your device.
Tips to shrink a PDF even further
- Use the Strong level for the smallest possible result.
- Convert colour scans to grayscale before compressing — colour data is heavy.
- Remove pages you don’t need, or split a huge file into smaller parts.
- Don’t re-compress an already-compressed PDF — you’ll lose quality with little size gain.
Why choose Ream
Email-ready in seconds
Slip under common attachment limits (often 10–25 MB) so your PDF actually sends instead of bouncing back.
You pick the trade-off
Three honest levels let you balance file size against image sharpness — no guessing, no one-size-fits-all.
Private by design
Files are processed in a network-isolated sandbox and wiped immediately afterwards. Nothing is stored, logged or shared.
Works on every device
Runs in your browser on Windows, macOS, Linux, iPhone and Android. No app to install, no account to create.
Frequently asked questions
How do I compress a PDF for email?
Add your PDF, choose Recommended (or Strong if it’s still too big), then download the smaller file and attach it. Most files drop well under typical 10–25 MB mail limits.
How do I get a PDF under 100 KB or a specific size?
Use the Strong level for the smallest result. Very small targets like 100 KB are realistic for short, text-light documents; large scans have a natural floor, but Strong gets you as close as the content allows without breaking readability.
Will compressing reduce the quality?
Only images are affected, and only as much as the level you pick. Recommended and Light keep documents looking clean on screen and in print; Strong trades a little image sharpness for the smallest size.
Why is my PDF barely smaller after compressing?
Because it’s mostly text, which is already compact — there’s little to remove. Compression shines on image-heavy PDFs like scans and photo reports, which can shrink by 50–80%.
Is it free, and are there watermarks or limits?
Yes, it’s free with no watermarks and no sign-up. Files can be up to 50 MB each.
Is it safe and private?
Your file is uploaded over an encrypted connection, processed in an isolated sandbox with no internet access, and deleted immediately afterwards. We never keep, read or share your documents.
Does it work on Mac, Windows and phones?
Yes. Ream runs in your browser, so it works the same on Windows, macOS, Linux, iPhone and Android — nothing to install.