CalculaIT / tools

PDF editor

Type, sign, highlight and white out content in a PDF, then download it.

Your PDF never leaves your computer: it is opened, edited and saved in your browser.

Quick answer · example

How do I edit a PDF for free without uploading it?

Open the PDF in the editor, choose a tool (Text, Signature, Image, Highlight or White out), click on the page and press Download PDF. Everything happens in your browser. To change existing text, cover it with White out and type over it.

Calculation assumptions

Add text, signatures, images, highlights and white-out to a PDF, rotate or remove pages and download it. Everything happens in your browser. Existing text cannot be edited: cover it and type on top.

View the worked example ↓

Formula and assumptions

pdf.js viewer (Apache 2.0) · writing with pdf-lib (MIT) · standard Helvetica, Times and Courier fonts · no file upload

Add text, signatures, images, highlights and white-out to a PDF, rotate or remove pages and download it. Everything happens in your browser. Existing text cannot be edited: cover it and type on top.

How to use this calculator

Fill in a form that is not editable, sign a contract, add a note or correct a detail without installing anything. The editor shows every page and lets you add text, drawn signatures, images, highlights and white rectangles, and rotate or remove pages. When you download, everything is built into the PDF.

Worked example

  1. Open the PDF by dragging it into the file area.
  2. Choose a tool and click or drag on the page; with Select you can move, resize or delete what you added.
  3. Press Download PDF to save a copy with your changes.

Interpreting the result

What you add is stored in the PDF and shows in any reader, but the original text is not rewritten: PDFs store individual letters placed on the page, not paragraphs. To correct a detail, use White out over the old text and type the new one on top. Note that white-out does not delete what is underneath: advanced tools could recover it, so do not use it to hide confidential data.

Frequently asked questions

Does the drawn signature count as an electronic signature?

It is an image of your signature, fine for many informal procedures. It is not a qualified electronic signature backed by a certificate; for that, use a certificate-based signing tool.

Why do some characters come out as question marks?

The standard PDF fonts cover the Latin alphabet with accents and €, but not other alphabets or emoji. The editor warns you if it had to replace any.

Can I keep editing later?

Yes. Open the downloaded PDF again and add what you need. What you added before is now part of the page and cannot be moved.

References and method

References and method