Crop PDF Margins — Free & Private
Trim wide white borders off a PDF so the content fills the page — great for tightening scans, slides, and screenshots before printing. Set how much to cut from each side and download, all in your browser.
In short: drop a PDF, drag the four sliders to trim the top, bottom, left and right margins, and download. It runs on your device and nothing is uploaded. Important: cropping a PDF hides the trimmed area rather than deleting it — it is not redaction, and the section below explains what to do instead.
- Does cropping delete the trimmed content?
- No. It changes the page’s visible area and leaves everything else in the file. Anyone can undo it in a PDF editor. This is how PDF cropping works everywhere, not a limitation here.
- So can I use it to hide confidential information?
- No — please do not. The text is still in the document and recoverable. Real redaction removes the content, and the section below says how to get it.
- What is it good for, then?
- Tidying: removing scanner borders, trimming wide margins so the text fills a tablet screen, cutting off a header or footer that is in your way.
- Is my PDF uploaded anywhere?
- No. The crop is applied in your browser, so the document never leaves your device.
- Can I crop pages differently from each other?
- No — one set of margins applies to every page. A scanned book with alternating margins needs a different tool.
- Is it free, and is there a limit?
- Free, with no task, page or size limit. Sejda allows 3 tasks an hour on its free tier and Smallpdf 2 a day.
How to Crop a PDF
Drop the PDF onto the tool, or click to browse and select it.
Use the sliders to choose how much to cut from each side as a percentage.
The crop box is applied to every page instantly in your browser.
Download the cropped PDF — margins gone, content front and center.
Why Use Convertlo?
- 🔒 100% Private — the PDF never leaves your browser
- 🆓 Free forever — no account, no watermark, no limits
- ✂️ Per-side control — trim each edge independently
- 📐 Percentage based — one setting works across mixed page sizes
- 📄 Reversible in readers — cropping sets the crop box, content is retained
- 📱 Works on mobile — any modern browser, any device
Features
100% Private
No server, no upload — your PDF stays on your device.
Four Sides
Independent top, right, bottom, and left trim.
Percentage
Scales cleanly across A4, Letter, and mixed sizes.
Instant
Crops every page in seconds.
No Limit
No page or file-size cap in a session.
Mobile-Ready
Works on iPhone, Android, tablet, and desktop.
Cropping hides content — it does not remove it
This is the most important thing on the page, so it is near the top: cropping a PDF does not delete anything.
A PDF page carries two rectangles. The MediaBox is the physical page. The CropBox is the part a reader displays. Cropping sets a smaller CropBox and leaves everything else alone — the text, images and annotations in the trimmed strip are still in the file, exactly as they were, simply outside the window.
Demonstrated rather than asserted: trim 20% off a 400×400 page here and the result has a CropBox of 400×320 and a MediaBox still reading 400×400. Reset the CropBox in any PDF editor — a one-line change — and the hidden strip is back, with its text selectable and searchable. Some readers will even find it in a text search without being asked to.
This is not a shortcoming of this tool. It is what cropping means in the PDF format, and every cropping tool behaves this way, whether or not it tells you. What is a shortcoming is not saying so, because the obvious use for "cut the top off this page" is hiding a letterhead, a name, a figure or a signature — and someone doing that here would be publishing the very thing they meant to remove.
What to do instead
- If the content must be gone, use a tool with a real redaction feature (Acrobat’s Redact, or a command-line tool that rewrites the content stream) and then check the result — open it, select all, copy, and paste somewhere to see what comes out. Nearly every redaction failure that has made the news was a black rectangle drawn over live text.
- If the content can be flattened, convert the pages to images and rebuild a PDF from them: PDF to JPG, crop the images with Crop Image, then Image to PDF. The trimmed area genuinely does not exist in the result. The cost is that the text stops being text — no selecting, no searching, and a bigger file.
- If you only want it out of the way, which is the usual case, cropping here is exactly right and nothing above applies.
What cropping is genuinely good for
With the warning out of the way: cropping is genuinely useful, and the cases are all about making a document comfortable to read rather than about hiding anything.
- Scanner borders. A flatbed scan of a book or a page smaller than the glass comes with black or grey edges. Trimming them makes the document look deliberate and stops the borders dominating a thumbnail.
- Reading on a tablet or e-reader. An academic paper laid out for A4 has margins that waste a third of a small screen. Cropping them lets the reader zoom the text to fill the display — the single biggest improvement you can make to reading a PDF on a device.
- A header or footer in the way. A running header repeated on two hundred pages, or a footer with a draft watermark, can be cropped out for a reading copy.
- Slides with wide letterboxing. Exported presentations often sit in the middle of a larger page.
One thing cropping will not do is make the file smaller, and the reason is the same as the warning above: the hidden content is still stored. If size is the goal, Compress PDF is the tool.
One set of margins for every page
The four sliders set one margin each, as a percentage of the page, and that one setting applies to every page in the document. This suits the common cases — a scan, a paper, a slide deck — where every page has the same layout.
It does not suit a scanned book. Facing pages have mirrored margins: the gutter is on the right of a left-hand page and the left of a right-hand one, so one setting either leaves the gutter on half the pages or eats into the text of the other half. There is no odd/even mode here, and the capability table says so rather than leaving you to discover it.
A percentage rather than millimetres is deliberate too: a document whose pages are not all the same size — a report with a landscape chart in the middle — gets a proportional trim that behaves sensibly on both, where a fixed measurement would take a quarter off one and a sliver off the other.
A crop that would leave a page smaller than about 20 points in either direction is skipped for that page rather than applied, because a page with no visible area is not a result anyone wants and some readers refuse to open the file at all.
Capabilities at a glance
What this tool does and does not do, stated plainly. The “No” rows are the point, not an omission.
| Capability | Supported | Detail |
|---|---|---|
| What it does | ||
| Trim the visible margins on every page | Yes | Four sliders: top, right, bottom, left. |
| Pages stay fully editable and selectable | Yes | Nothing is re-rendered; the text is still text. |
| Deletes the trimmed content | No | It is hidden, not removed — see below. This is how PDF cropping works everywhere. |
| Redaction | No | Not what this is. Use a tool that removes content, then check the result. |
| Different margins per page | No | One set of margins applies throughout. |
| Crop by dragging on a preview | No | Sliders, with a live preview of the result. |
| Auto-detect and trim white space | No | You set the amounts. |
| Input | ||
| Any PDF | Yes | Including scans. |
| An encrypted PDF | No | Open it with Unlock PDF first. |
| Page or size limit | No | There is no server to protect. Sejda caps the free tier at 50 pages and 50 MB. |
| Task limit | No | Smallpdf allows 2 free tasks a day, Sejda 3 an hour. |
| Output | ||
| A normal PDF with smaller pages | Yes | Opens and prints anywhere. |
| A smaller file | No | The hidden content is still stored, so the size barely changes. |
| The original left untouched | Yes | The result is a new download. |
| Watermark | No | Nothing is added to the pages. |
| How it runs | ||
| Nothing is uploaded | Yes | The document never leaves your device. |
| Signup | No | There is no account. |
| Offline use | No | The page and pdf-lib load from the network first. |