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  3. PDF Cropper
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PDF Cropper

Crop PDF page margins to remove whitespace

Trim the margins of PDF pages to focus on the content that matters. You set how much to cut from the top, bottom, left, and right (in points, where 72 points equals 1 inch), either with the per-side sliders or with quick presets like Small, Medium, Header Only, or Binding Edge. The same crop is applied uniformly to every page by adjusting each page's crop box, and a simple diagram shows in red roughly how much will be trimmed from each side.

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PDF Cropper: a worked example

Scanned pages have huge white margins that waste space when printed two-up.

Input

scan.pdf · crop 18 mm off each margin, all pages
PDF Cropper produces

Output

scan.pdf with tightened margins, content centred

Cropping adjusts the visible page box so the content fills more of the sheet, improving print density and on-screen readability without resampling anything. A uniform crop across pages keeps the document consistent.

About the PDF Cropper

Trim the margins of PDF pages to focus on the content that matters. You set how much to cut from the top, bottom, left, and right (in points, where 72 points equals 1 inch), either with the per-side sliders or with quick presets like Small, Medium, Header Only, or Binding Edge. The same crop is applied uniformly to every page by adjusting each page's crop box, and a simple diagram shows in red roughly how much will be trimmed from each side.

Working with your PDF

  1. 1Upload the PDF you want to crop.
  2. 2Pick a preset or set the top, bottom, left, and right margins (in points) with the sliders.
  3. 3Optionally link the sliders to change all sides together, then download. The crop applies to all pages.

Key features

  • Per-side margin sliders with optional linked adjustment
  • Quick presets (Small, Medium, Large, Header Only, Binding Edge, and more)
  • Margin input in points (72 pt = 1 inch)
  • Applied uniformly to every page via the page crop box

Common scenarios

  • Removing large margins

    Trim excessive whitespace from scanned documents or academic papers for easier reading on small screens.

  • Preparing print-ready files

    Crop pages to a specific size required by a print shop or binding service.

Tips & best practices

  • Cropping here only sets the /CropBox, so the hidden content is still in the file - to truly remove sensitive marginalia use redaction or rasterization, not this tool.
  • Don't expect a smaller file after cropping: since the trimmed-away marks remain embedded, the saved PDF is usually about the same size as the original.
  • Sliders move in 5pt steps, so for an exact inch use 72pt; half an inch (36pt) is not reachable, so pick 35pt or 40pt instead.

Examples

  • Remove a 0.75-inch scanner border on all sides

    Enable the Linked toggle and drag any slider to 54pt (0.75 x 72 = 54). All four margins follow, trimming the black scan border off every page. The Total Crop readout shows 216pt.

  • Trim only the running header

    Click the Header Only preset to set Top to 72pt while Bottom, Left, and Right stay at 0, hiding the top inch of every page in the viewer without touching the other edges.

How it works

PDF Cropper trims page margins by setting four independent values - Top, Bottom, Left, and Right - each controlled by a slider that runs from 0 to 200 points in steps of 5 (the tool notes that 72 points equals 1 inch). There is no draggable crop box: the preview is a fixed illustration of a single page with red overlays whose thickness scales with each margin value, labeled with the point amount on each edge. Eight quick presets are available: None, Small (10pt all sides), Medium (25pt all sides), Large (50pt all sides), Extra Large (100pt all sides), plus three asymmetric ones - Header Only (72pt off the top), Footer Only (72pt off the bottom), and Binding Edge (72pt off the left). A Linked/Independent toggle lets you drive all four sliders to the same value at once, and a running 'Total Crop' counter sums the four margins; the Crop PDF button stays disabled until at least one margin is non-zero.

Under the hood the cropPDF function uses the pdf-lib library: it loads the file with PDFDocument.load, iterates every page, reads each page's width and height, and calls page.setCropBox(left, bottom, width - left - right, height - top - bottom). Because the same four margin values are passed for every page, cropping is applied uniformly across the whole document - there is no per-page selection in this build. Crucially, setCropBox only redefines the /CropBox, which is the visible rectangle a viewer displays; it does not delete or rewrite the underlying page content. The text, images, and marks that fall outside the new crop box are still present in the saved file. This is why cropping a PDF here rarely reduces the file size, and it is also why cropping is not a way to hide sensitive marginalia: anyone who resets or enlarges the crop box in another viewer can recover the trimmed-away content. For genuine removal you need redaction or rasterization, not a crop-box change.

Everything runs in the browser - the file is read with file.arrayBuffer() and processed client-side, never uploaded. On load the tool calls getPDFInfo to read and display the page count, then the crop step downloads the result as <originalname>_cropped.pdf with an application/pdf MIME type. A practical worked example: a page scanned with a 0.75-inch black border on every side needs 54pt on all four sliders (0.75 x 72), which you can set quickly by enabling the Linked toggle and dragging any one slider to 54. Note the 5pt slider granularity means you can only set margins in multiples of 5 from the UI, and presets like Header Only and Footer Only deliberately leave the other three sides at 0 so only one edge is trimmed.

Frequently asked questions

Does cropping reduce file size?

Cropping changes the visible area but may not significantly reduce file size, since the hidden content can still be stored in the file. Use the compressor for size reduction.

Can I undo a crop?

The original file is not modified. Re-upload it to start fresh if needed.

Related tools and how they differ

  • PDF Rotator: Rotates page orientation in 90 degree steps per page, selection, or all pages without changing dimensions; use it to fix sideways or upside down scans, not to trim margins.

Private by design

PDF parsing and editing happen in your browser. Documents, and everything inside them, are never uploaded or stored remotely.