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Flatten PDF

Flatten PDF is part of Toolspire and is ready as soon as this page loads. Lock a filled-in form, signature or annotated PDF so fields can’t be changed and comments look the same in every app — or turn every page into an image. Runs in this tab; nothing is uploaded.

Runs in this tabFreeNo account

On this page

What you can do here

Lock filled forms

Send a completed application, tax form or agreement knowing the values can’t be changed by the next person who opens it.

Same look everywhere

Form values and comments can look different — or vanish — in some viewers and when printed. Flattened, they always show.

Know what’s inside

See how many form fields and comments your PDF has before you flatten it, and what’s left afterwards.

Two strengths

Keep searchable text with Forms & comments, or choose Everything to images for a page no one can edit or copy.

Portal-friendly

Some upload portals reject fillable PDFs or lose the values. A flattened PDF is accepted like any scanned document.

Private

Your form stays on your device. No upload, no account and no watermark.

The sequence

How to flatten a PDF

  1. 1

    Open the PDF

    Drop the filled form or annotated PDF onto the box. Enter its password if it has one.

  2. 2

    Check what’s in it

    The tool shows how many form fields and comments or drawings it found.

  3. 3

    Choose how

    Pick Forms & comments (recommended) or Everything to images, with an image quality.

  4. 4

    Flatten and download

    Click Flatten PDF. The flattened copy downloads and the tool confirms nothing editable is left.

Worth knowing

  • Flatten PDF on Toolspire: Flattening turns interactive parts of a PDF — form fields, checkboxes, dropdowns, comments, highlights, stamps and drawn signatures — into ordinary page content that can’t be edited.
  • The tool first counts the form fields and comments in your file, so you know what will be flattened.
  • Forms & comments mode keeps text selectable and the file small; filled values look exactly as they did in the form.
  • Everything to images mode turns each page into a picture at 150, 200 or 300 DPI, so nothing can be selected, copied or edited.
  • Links and bookmarks are kept in Forms & comments mode.
  • Password-protected PDFs can be flattened after entering the password; the flattened copy has no password.
  • Runs entirely in this tab with QPDF (WebAssembly) and PDF.js — the file is not sent to us.

Which mode should I use?

Forms & commentsEverything to images
Form fields and commentsLocked into the pageLocked into the page
Text can be selected and searchedYesNo
Page content can be edited in a PDF editorHarder, but possibleNo — only as a picture
File sizeAbout the sameLarger (depends on quality)
Links and bookmarksKeptRemoved
Best forForms, signed agreements, reviewed draftsDocuments you don’t want copied or changed

When to flatten a PDF

Flatten a form after filling it in and before sending it — for example a job application, a KYC form, a bank mandate or a government form. It stops anyone accidentally or deliberately changing the answers, and makes sure the values print.

Flatten a reviewed document to make comments, highlights and sticky notes a permanent part of the page, so they show in every viewer and on paper.

Keep your original! A flattened PDF can’t be filled in again. To stop others copying or printing too, protect the PDF after flattening; to hide personal details, use Redact PDF.

FAQ

Questions about Flatten PDF

Where does Flatten PDF run?

Flatten PDF runs in this tab on Toolspire. What you type or drop in is not sent to us and is not stored on a server.

What does it mean to flatten a PDF?

Flattening merges interactive layers — form fields, comments, stamps and signatures — into the page itself. The PDF looks the same, but those parts can no longer be clicked, changed or deleted separately.

Can a flattened PDF be unflattened?

No. The fields are gone, so the form can’t be filled in again. Keep your original if you might need to change it.

Will my digital signature still be valid?

No. Flattening changes the file, so a cryptographic (certificate) signature will no longer verify, although it still appears on the page. Flatten before signing if the signature must stay valid.

Is my form uploaded anywhere?

No. Flattening runs in this tab with WebAssembly, and the file never leaves your device.

Why does it say some things are still editable?

A few comments, such as some sticky notes, don’t store how they look, so they can’t be merged into the page and are left as they were. Choose Everything to images to lock in everything you see.

Can I flatten a PDF without form fields?

Yes, with Everything to images. It turns each page into a picture, so the text can’t be selected, copied or edited.

Keep going

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