How to Crop a PDF Online Free (Trim Margins and Scan Edges)
Remove white margins, scanner edges and unwanted borders from your PDF with a live preview. Free, no watermark.
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Scanned documents almost always come with a black border, a shadow along one edge, or several centimetres of dead white space. On a phone, those margins shrink actual content to an unreadable postage stamp. Cropping fixes it in about thirty seconds.
When cropping is worth doing
Scans with black or grey edges, photographed documents with desk visible around the page, slide handouts with huge empty borders, reading on a phone (trimming margins can make text 30-40% larger without zooming), or reprinting after removing an old header.
Step 1: Upload your PDF
Open Crop PDF and select your file. The first page appears in the preview panel immediately.
Step 2: Drag the edge sliders
Four sliders — Top, Bottom, Left, Right — each trim that edge by a percentage. The preview shows a shaded red area for what gets removed and an outlined box for what you keep. Most scans need 3-8% off each edge; desk photos often need more. Each slider stops at 45% so you can't crop away the entire page.
Step 3: Download
Hit Crop & Download. The crop applies uniformly to every page, so a hundred-page scan crops as fast as a one-page one.
How cropping actually works
DesiDocs adjusts the page's crop box — a value telling readers which region to display. Nothing is deleted, there's zero quality loss because pages aren't re-rendered, it's reversible, and it's instant even on large files.
Uniform crop vs per-page
DesiDocs applies the same crop to every page, which is correct almost all the time since a scanner produces the same margins throughout. If a few pages genuinely differ, split, crop each part, then merge back.
Cropping to shrink file size
Cropping alone won't shrink file size much since the content is still there — only the visible display region changes, not the underlying image data. For an actual size reduction, crop first for looks, then run Compress PDF.
Cropping for readability on mobile
This is worth calling out on its own because it's the reason most people crop a PDF who aren't dealing with a scanner artifact at all. A typical A4-formatted document has generous side margins meant for print, but on a phone screen those margins just eat space that could be text. Trimming 8-10% off each side edge before reading on a phone can genuinely make the visible text noticeably larger without any pinch-zooming, especially for dense documents like judgments, research papers or long contracts you're reading start to finish on a commute.
A crop mistake worth avoiding
Cropping too aggressively on one edge can clip actual content rather than margin — the preview panel exists precisely to catch this before you download, since it's easy to drag a slider a bit too far while eyeballing it. Always check the preview against the full page, not just the cropped result, so you can confirm you haven't cut into a paragraph, a signature line, or a table's last column.
Privacy
Your file is encrypted in transit, cropped on a secure server, and automatically deleted within 30 minutes of upload.
Frequently asked questions
Can I crop just one page? Not directly — split, crop, and merge for per-page control.
Will text still be selectable? Yes, only the page box changes; the underlying content is untouched.
Does it work on scanned images inside a PDF? Yes, the same way — cropping adjusts the visible page region regardless of whether the page is text, an embedded scan image, or a mix.
Is cropping reversible? Not within the same file once downloaded, so keep your original if you might need the full page again later.
Try it now with Crop PDF.
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