Flatten PDF
Merge form fields and annotations into the page so they can no longer be edited.
Drop your PDF here, or click to select
Single PDF file · Max 100MB
Lock filled form fields and annotations into the page
An interactive PDF keeps its form fields, checkboxes, and comment markups as a live layer that sits on top of the page rather than inside it. Anyone who opens the file in Acrobat, a browser, or Preview can still click into those fields and change the values. Flattening collapses that interactive layer down into the static page content, so what you see becomes what everyone gets — permanently.
When flattening actually matters
- Sending a signed agreement. You filled an AcroForm contract, typed the date, and ticked the consent boxes. Email it as-is and the recipient (or a forwarder) can silently retype any field. Flatten first and the values are frozen into the page.
- Form data that won't display the same everywhere. Some mobile and third-party PDF viewers render empty form widgets, drop default field appearances, or mis-handle field fonts. After flattening there are no widgets left to misrender — the text is just part of the page, so it looks identical in every viewer.
- Printing and archiving. Print pipelines and document-management systems often ignore the annotation/form layer or print it inconsistently. A flattened file prints exactly as shown and is a far safer thing to store long-term.
- Stopping accidental edits. A teacher distributing a marked worksheet, or HR sending an offer letter, wants the content visible but not casually editable. Flattening removes the temptation without needing a password, and any reviewer comments or stamps get baked in too.
How it works under the hood
The tool runs Apache PDFBox's PDAcroForm.flatten() on the server. That walks the document's AcroForm, renders each field's current appearance stream (the visual the field is showing right now) directly into the page's content stream, then removes the field widgets and the form dictionary. Annotations get merged into the page in the same pass. The page geometry, fonts already embedded for the field text, and your entered values are preserved — only the interactivity is stripped. Because the visible appearance is what gets drawn, you should fill the form completely before uploading: empty or half-filled fields flatten to whatever they currently show.
Practical tips
- Always keep your original editable PDF. The flattened copy can't be turned back into a form here or anywhere else — the fields no longer exist as objects.
- Want to also prevent the file from being opened or re-saved? Flatten removes editability of fields, not document permissions. Run the result through [Protect PDF](/protect-pdf) to add an AES password.
- Flattening doesn't shrink files much on its own. If the document is large, follow up with [Compress PDF](/compress-pdf).
When to use a different tool
- You need to add a handwritten signature image, not lock an existing form — use [Sign PDF](/sign-pdf), which stamps a PNG signature onto the page.
- You want to draw, highlight, or cover content as an overlay rather than freeze form fields — use [Edit PDF](/edit-pdf). Note that neither tool rewrites the original text layer.
- You want a faint "Draft" or "Confidential" label across pages — that's [Watermark PDF](/watermark-pdf), which you can run before flattening so the label becomes permanent too.
How it works
- Upload the PDF form or annotated document you want to flatten.
- Click Flatten to merge all form fields and annotations into the page content.
- Download your flattened, uneditable PDF in seconds.
Frequently Asked Questions
Why should I fill in the form completely before flattening?
Flattening draws each field's current appearance into the page, so whatever a field shows at upload time is what gets frozen. Empty or half-filled fields flatten to blank — fill everything in first, because the values can't be edited back afterward.
Does flattening guarantee no one can ever extract the text?
No. The values become ordinary page text and graphics, which is exactly what makes them display and print reliably — but that text stays selectable and copyable. Flattening removes form interactivity, it does not hide or encrypt content.
What happens if my PDF has no form fields or annotations?
Nothing harmful. With no AcroForm and no annotations there is nothing interactive to collapse, so you get back an equivalent PDF with its page content unchanged.
Can a flattened PDF be turned back into an editable form?
No. The field widgets and form dictionary are removed permanently, so the fields no longer exist as objects to edit — here or in any other tool. Keep your original editable PDF if you may need to change the form later.
Does flattening also lock the document so it can't be re-saved?
No. It only removes form-field and annotation interactivity, not document permissions. To stop the file being opened or re-saved, run the result through Protect PDF to add an AES password.
Will flattening make my PDF smaller?
Not by much on its own — it strips the interactive layer, not embedded fonts or images. If size matters, follow up with Compress PDF after flattening.