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Local PDF tool - browser processing

Crop a PDF without uploading

Cropping a PDF without uploading means trimming margins, scanner borders, or visible edges in your browser and exporting a cleaner copy. You drag the crop box around the content you want to keep, choose the scope, and export — the PDF stays on your device from open to download.

Crop locally See the proof

0 bytes sent proof

What the widget measures

The panel counts what leaves your browser after you choose a file. The site's own scripts and fonts load like any web page — what you will never see is a request carrying your PDF. Check it here, or open your browser's Network tab and see for yourself.

0 bytes of your document sentStarts measuring when you choose a file on a tool page
Document request bodies
0 bytes
App network after file open
0 bytes
Processing engine
Browser WASM worker

The number is scoped to request bodies after you choose a document. App assets such as JavaScript, WASM, and fonts can still load; those are not your PDF bytes.

Verify it yourself
  1. Open DevTools, then the Network tab.
  2. Choose a PDF in the tool and complete the action.
  3. Filter for fetch or XHR requests; document processing should not create a request carrying your file.

Stronger check: load the tool page first, then disconnect from the network before choosing the file. Already-loaded tool code can continue processing locally, but a first visit still needs the site assets.

Local vs. online

How local processing compares

Doing this in Lemmafour keeps the file on your device. A typical online PDF tool uploads it to a server first — here is the practical difference:

  Typical online PDF tool Lemmafour
Where your file goes Uploaded to the provider’s servers Stays in your browser — never uploaded
Works offline No — it needs a round trip to their server Yes, once the page has loaded
Account or sign-up Often required Never — no account, no email
What they keep afterwards Your file sits on their servers until they delete it Nothing to keep — it never left your device

Steps

How to do it in Lemmafour

  1. Choose Crop locally.
  2. Open the PDF.
  3. Select Crop in the toolbar.
  4. Drag the crop handles around the visible content you want to keep.
  5. Choose the apply scope, export, and review the result.

Expert note

Crop does not erase hidden content

PDF crop boxes can hide page regions without necessarily removing every underlying object from the file. Do not use crop as redaction. If margin content is sensitive, use secure redaction or delete the page content before sharing.

FAQ

Questions people ask before using this tool

Can I crop every page?

Yes. Use the crop scope controls to apply the crop beyond the current page where appropriate.

Will crop reduce file size?

Not reliably. Crop is a layout operation, not compression.

Can I crop scanned PDFs?

Yes, but it trims visible page area; it does not OCR or rewrite the scan.

Related private PDF workflows

Keep working locally

Rotate a PDF without uploading Rotate PDF pages locally in your browser and export a corrected copy. Prepare a PDF for print without uploading Use Print Doctor locally to check page size, orientation, margins, and print risks before exporting. Remove a watermark from a PDF locally Use Clean PDF to select repeated watermark-like objects and remove matching copies locally in your browser. Redact a PDF without uploading Use secure redaction mode locally in your browser and verify that redacted text is not recoverable. PDF tool hub Browse the shipped local PDF tools.