PDF Cropper
PDF Cropper
Drag and drop your PDF here, or click to browse
Supported format: PDF only. Processed entirely in your browser.
Upload a PDF to Get Started
Drop a PDF file into the upload area, set your margin values, and click Crop PDF to trim the page boundaries and download the result.
Trim margins and crop pages — entirely in your browser, nothing uploaded
PDF files frequently arrive with oversized margins, scanner borders, watermark gutters, or excess whitespace that wastes paper and screen space. Whether you are preparing a document for printing on a specific paper size, removing the black borders left by a flatbed scanner, tidying up a research paper before sharing, or extracting a clean content area from a presentation slide, a PDF cropper is the fastest way to get the result you need without reformatting everything from scratch. Our PDF Cropper runs entirely inside your web browser using pdf-lib, a powerful JavaScript library that reads and modifies PDF files without sending any data to a server. Your document never leaves your device — a critical advantage over most online PDF tools that upload your files to third-party cloud servers. This makes our tool suitable for confidential reports, legal documents, medical records, and any other sensitive material you need to process privately. Cropping a PDF works by adjusting the CropBox — a metadata rectangle defined in the PDF specification that tells viewers which part of the page to display. The content outside the CropBox is hidden but not permanently deleted, which means the crop is technically non-destructive. You can always open the file in a full PDF editor later and restore the original margins if needed. This approach preserves text searchability, embedded fonts, vector graphics, and all other PDF features without recompression or quality loss. Using the tool is straightforward. Upload your PDF by dragging it into the drop zone or clicking to browse. Select your preferred unit (millimetres or inches) and enter the margin amounts you want to remove from each side: Top, Right, Bottom, and Left. A top margin of 20 mm, for example, removes 20 mm from the top of each page. You can apply the crop to all pages simultaneously or specify a custom page range such as 1-3,5,8-12 to process only the pages that need trimming. When you click Crop, the tool applies a CropBox to every target page in milliseconds and makes the resulting file available to download immediately. For common scenarios, use one of the built-in presets. "No Margins" sets all four margins to zero, which is useful when you want to remove crop marks added during print production. "Equal Margins" propagates the top margin value to all four sides in a single click. "Print Margins" adds standard 25 mm (1 inch) margins on all sides — helpful when you need to add breathing room to a document that currently bleeds to the edge. Because the tool runs locally, processing speed depends only on your device's CPU, not on server queue times or network bandwidth. A 200-page document with uniform margins typically completes in under two seconds on a modern laptop. There are no file-size limits imposed by server infrastructure — your browser's available memory is the only constraint, and modern browsers handle files up to several hundred megabytes without difficulty. PDF cropping is commonly used by students removing scanner shadows from scanned textbooks, office workers trimming presentation slides exported as PDFs, designers isolating artwork from a multi-page template, and publishers preparing print-ready PDFs from submissions. In each case, the ability to specify precise margin values in millimetres — matching real-world measurements — makes the tool far more accurate than visual drag-to-crop interfaces that depend on pixel estimation. After cropping, always review the result in a standard PDF viewer such as Adobe Acrobat, Preview (macOS), or your browser's built-in PDF viewer before distributing the file. Check that no essential content has been clipped at the edges, particularly on pages that may have slightly different layouts or margins than the first page. If a page range crop was applied, verify that the untreated pages still look correct.
Understanding PDF Cropping
What Is PDF Cropping?
PDF cropping is the process of adjusting the visible page area of a PDF document by modifying one or more of the page boundary boxes defined in the PDF specification. The most commonly adjusted boundary is the CropBox, which defines the region of the page that PDF viewers display and print. When you crop a PDF, you are instructing viewing applications to show only the area inside the CropBox and ignore everything outside it. Unlike image cropping, PDF cropping is non-destructive by default — the hidden content remains embedded in the file and can be revealed again by resetting the CropBox. This makes PDF cropping reversible, which is a key advantage over rasterising the document and cropping the resulting images.
How Does the Tool Calculate the CropBox?
The PDF coordinate system places the origin (0, 0) at the bottom-left corner of each page, with y values increasing upward. All measurements inside a PDF file are expressed in points (pt), where 1 point equals 1/72 of an inch. To apply your margin inputs, the tool first retrieves the current MediaBox dimensions for each target page — this represents the full physical page size. It then converts your margin values from millimetres (1 mm = 2.83465 pt) or inches (1 inch = 72 pt) into points. The new CropBox is computed as: x = left margin in points, y = bottom margin in points, width = page width minus left and right margins, height = page height minus top and bottom margins. The resulting CropBox rectangle is written back into the PDF for each processed page.
Why Does Cropping Matter?
Proper PDF cropping improves readability, reduces visual clutter, and ensures consistent presentation across different viewing environments. Scanner-produced PDFs often include black border artifacts from the scanner glass edges, which are distracting and waste ink when printed. Academic papers and reports downloaded as PDFs sometimes have very wide margins that reduce the effective reading area on screen, particularly on tablets and e-readers. Presentation slides exported as PDFs may include large white gutters around the slide content area. Removing these unwanted areas makes the document look more professional, reduces file rendering time in some viewers, and ensures that the content fills the available screen space when displayed in full-page mode.
Limitations to Be Aware Of
PDF cropping via CropBox adjustment hides content but does not reduce file size, because the hidden content remains in the file data. If file size reduction is important, you need a PDF optimiser or compressor after cropping. Auto-crop whitespace detection (available in some tools) requires rendering pages to a canvas, which is memory-intensive and may not work reliably for scanned documents with slightly off-white backgrounds. Pages in a PDF may have different dimensions — for example, a mix of portrait and landscape pages — in which case applying uniform margin values produces different visual results on each page type. Always check the cropped output on a sample of pages before distributing. Password-protected PDFs with editing restrictions cannot be modified without the owner password.
How to Crop a PDF
Upload Your PDF
Drag your PDF file into the upload area or click the box to open your file browser. Only PDF files are supported. Your file stays in your browser — nothing is uploaded to a server.
Set Your Crop Margins
Choose millimetres or inches, then enter the amount to remove from each side: Top, Right, Bottom, and Left. Use a preset — No Margins, Equal Margins, or Print Margins — to fill in common values quickly. Leave a field empty or set it to 0 to keep that edge unchanged.
Choose Which Pages to Crop
Select 'All Pages' to apply the same crop to every page in the document. Choose 'Custom Page Range' and type a range such as 1-3, 5, 8-12 to crop only specific pages. Pages not included in the range are left exactly as they are.
Download the Cropped PDF
Click 'Crop PDF' to process the file. The results panel shows the original and cropped dimensions, the number of pages affected, and the percentage of page area removed. Click 'Download Cropped PDF' to save the file to your device.
Frequently Asked Questions
Does cropping a PDF reduce its file size?
Not directly. Standard PDF cropping works by adjusting the CropBox boundary, which tells PDF viewers which portion of the page to display. The content outside the CropBox remains embedded in the file — it is hidden rather than deleted. As a result, the file size stays roughly the same after cropping. If you need to reduce file size, use a PDF compressor or optimiser after cropping. Some tools can flatten the CropBox into the MediaBox (a destructive operation that truly removes the hidden content), but this requires re-rendering the pages and may reduce text sharpness.
Is my PDF uploaded to your servers?
No. This tool is entirely client-side, powered by the pdf-lib JavaScript library running in your browser. Your PDF file is read from your local disk, processed in browser memory, and written back to your disk when you download. No data is transmitted over the internet at any point. This makes the tool suitable for confidential documents — legal contracts, medical files, financial reports — that you would not want to upload to a third-party cloud service.
Can I crop different margins on different pages?
The current version applies the same Top/Right/Bottom/Left margin values to all pages in the selected range. If you need different crops on different page groups — for example, different settings for odd and even pages in a booklet — process the PDF in multiple passes: first crop the odd pages by entering their range (1, 3, 5…), download, re-upload, then crop the even pages with a different range and different margin values. This workflow achieves per-group cropping without any single pass needing to handle variable margins.
What happens if my margin values are too large?
If the combined left and right margins exceed the page width, or the combined top and bottom margins exceed the page height, the resulting CropBox would have zero or negative dimensions — which is invalid. The tool detects this condition before processing and shows an error message asking you to reduce your margin values. A good rule of thumb is to keep each pair of opposing margins (left + right, or top + bottom) below 80% of the respective page dimension, leaving at least 20% of the page visible after cropping.
Will cropping affect the text, images, or fonts in my PDF?
No. CropBox-based cropping is entirely non-destructive. The tool only modifies the boundary metadata in the PDF — the actual page content stream, embedded fonts, vector graphics, and images are completely untouched. Text remains fully searchable and copyable. Images retain their original resolution. The visual quality of content inside the cropped area is identical to the original. This is one of the key advantages of PDF-native cropping compared to converting the PDF to images, cropping those images, and reassembling them into a new PDF.
Why does the tool show a percentage 'area removed' instead of just dimensions?
The area reduction percentage gives you an intuitive sense of how much of each page you have trimmed. For example, removing 15 mm from all four sides of an A4 page (210 × 297 mm) reduces the visible area from 62,370 mm² to around 42,840 mm² — a 31% reduction. This single number lets you quickly verify whether the crop is as aggressive as intended or whether you may have entered values in the wrong unit (for example, entering inches values while mm is selected). The original and cropped dimensions in your chosen unit are also shown for precise verification.