Flatten PDF
Make a filled-in PDF read-only — flatten the form fields while keeping the text searchable, or flatten the whole page to an image. Your file never leaves your device.
Nothing Is Uploaded
The PDF is flattened entirely in your browser. Your form — and any personal data on it — never touches a server, and the tool keeps working offline.
Truly Read-Only
Filled form fields are merged into the page and can no longer be edited, filled, or accidentally changed — exactly what e-filing and signed documents need.
Text Stays Searchable
Flattening form fields keeps your text as real text, not a picture — so it stays searchable and selectable. Most tools never tell you this.
Two Flatten Modes
Flatten just the form fields (searchable), or flatten the whole page to an image to lock annotations and stamps too. You choose.
TL;DR: Flatten a PDF right in your browser to make it read-only. Flatten form fields to lock a filled-in form while keeping the text searchable, or flatten the whole page to an image to lock annotations and stamps too. Flattening is permanent, so keep a copy of the original. No upload, no signup, no limits.
Why Flatten a PDF?
A filled-in PDF form is still editable — anyone who opens it can change the values, and a stray click can wipe a field. Flattening fixes that by merging the interactive parts into the page so the document becomes read-only. It's how you finalise a signed contract, stop a recipient from altering a form you sent, and make sure annotations and stamps print the same in every reader. Court and government e-filing systems (such as CM/ECF) often require flattened PDFs and will reject forms that still have live fields.
What's different here is where the work happens. The usual online flatteners upload your document to a server and promise to delete it later — typically after 30 minutes to a couple of hours — and Adobe locks flattening behind a paid Acrobat Pro subscription. This tool flattens the PDF entirely on your device: the file is parsed and rebuilt by code running in your browser tab, and the read-only result is saved straight to your downloads. Nothing is sent, so there is nothing to delete.
What Does Flattening a PDF Actually Do?
Flattening a PDF merges interactive elements — form fields, and in image mode also annotations and stamps — into the static page content. The result looks identical but can no longer be edited or filled in. Flattening is permanent and cannot be undone.
Because it's irreversible, keep a copy of the original if you might still need to edit it. Once flattened, the form fields are gone: what's left is a flat drawing of how the page looked, which is exactly why it can't be tampered with.
"Flatten" gets used for a few different jobs, and they're worth separating. This tool flattens form fields and annotations — the most common need. Flattening optional-content layers (OCG) and flattening transparency for professional print/prepress are different operations handled by Acrobat Pro or Illustrator, and this tool does not do those.
Two Ways to Flatten: Keep Text Searchable, or Lock Everything
Flattening isn't one-size-fits-all. This tool gives you two modes, and the right one depends on whether you need the text to stay searchable:
Flatten form fields (recommended)
Only the form fields are merged into the page. The text — including the values you typed — stays real, searchable, and selectable, because it isn't turned into a picture. It's fast, lossless, and keeps the file small.
Best for read-only forms, signed contracts, and court e-filing (CM/ECF).
Flatten to image
Every page is rendered to an image and rebuilt into a new PDF, so everything — form fields, annotations, highlights, stamps — is locked. The trade-off: the text becomes part of the image, so it's no longer searchable or selectable, and the file may be larger.
Use when you need everything locked, including free-form markup, or a true what-you-see-is-what-you-get copy.
Flatten a PDF Without Uploading It
Almost every flatten tool online — Sejda, PDF24, Smallpdf — sends your document to a server and answers the privacy question with a deletion timer: 30 minutes, one hour, two hours. Adobe goes further and requires a paid Acrobat Pro subscription. That's a lot of trust for a file that's often a signed contract or a form full of personal details.
This tool skips the trip. The PDF is opened in your browser tab, flattened by JavaScript running on your device, and the result is assembled locally. Load the page, disconnect from the internet, and flatten the PDF anyway — that's the whole privacy policy, verifiable in ten seconds.
How to Flatten a PDF in 3 Steps
- 1
Open your PDF
Drag and drop the file onto the tool above, or click to browse. The PDF loads locally in your browser — nothing is sent over the network.
- 2
Choose a flatten mode
Pick "Flatten form fields" to lock the form while keeping the text searchable, or "Flatten to image" (with a DPI setting) to lock annotations and stamps too. Need it for court e-filing? Use flatten form fields.
- 3
Flatten & download
Click "Flatten & Download PDF". A new read-only file is built on your device — the original stays untouched. Remember that flattening can't be undone.
What You Can Use This For
A handful of situations cover almost every reason people flatten a PDF:
Finalise a filled-in form
Lock the values you typed into a fillable PDF so they can't be changed, and the form reads as a finished document.
Prepare a court or e-filing PDF
Court systems like CM/ECF reject PDFs with live form fields. Flatten the form fields and the document passes — with the text still searchable.
Lock a signed contract
After signing, flatten the PDF so neither party can alter fields or the signature placement afterwards.
Make annotations print consistently
Comments, highlights, and stamps can move or disappear in different readers. Flatten to image to burn them permanently into the page.
Stop recipients editing your form
Send a read-only PDF so a reviewer can see the filled values without accidentally — or deliberately — changing them.
Lock a sensitive document before sharing
Flatten to image for a fully static, what-you-see-is-what-you-get copy with no editable layers left behind.
Flatten vs Compress vs Sign
These jobs are easy to confuse because they all "finish" a PDF. They do completely different things:
Make it read-only
Merges form fields (and in image mode, annotations) into the page so nothing can be edited or filled in. Permanent. Use it to finalise forms, contracts, and e-filing documents.
Reduce the file size in MB
Shrinks the megabytes for email or upload limits by re-encoding images and fonts. Flattening doesn't reliably reduce file size — compression does.
Compress PDF →Add a signature
Draw, type, or place a signature on the page. Many people flatten right after signing so the signature and fields can't be moved — the two pair well together.
Sign PDF →Browser-Based vs Upload-Based PDF Flatteners
Every tool that can flatten a PDF works either on a company's server or on your own device:
| Aspect | This tool (in your browser) | Typical online flatteners |
|---|---|---|
| Where your file goes | Never leaves your device | Uploaded to a server |
| Account or payment | Free, no account | Adobe needs paid Acrobat Pro |
| Keeps text searchable | Yes, in form-field mode | Often unclear or rasterized |
| Flatten modes | Form fields or full image | Usually one fixed behaviour |
| Limits | No size, page, or task limits | Hourly quotas and size caps on free tiers |
| Works offline | Yes, once the page is loaded | No |
One scope note: flattening makes a PDF read-only, but it won't reliably make the file smaller in megabytes, and it isn't the same as encrypting it. If you need a smaller file, compress it; if you need a password, that's a separate step — and flattening transparency for professional printing is an Acrobat Pro / Illustrator job, not this one.
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Make forms read-only — keep text searchable or lock to image
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Frequently Asked Questions
Everything people ask about flattening a PDF
What does "flatten a PDF" mean?
It merges interactive elements into the static page so they can't be edited. Form fields — and in image mode, annotations and stamps — become part of the page content. The PDF looks identical but is now read-only, which is why flattening is used to finalise forms and signed documents.
Is flattening a PDF reversible?
No — flattening is permanent. Once a PDF is flattened, the form fields and interactive layers are gone and can't be brought back. Always keep a copy of the original if you might still need to edit it.
Will my text stay searchable after flattening?
Yes in form-field mode, no in image mode. Flattening form fields keeps the text as real, searchable text. Flatten to image renders each page to a picture, so the text becomes part of the image and is no longer searchable or selectable.
How do I flatten a PDF for court or e-filing (CM/ECF)?
Use the "Flatten form fields" mode. It locks the form fields so the filing system accepts the document, while keeping the text searchable as most e-filing rules require. Upload the file, choose flatten form fields, and download — all in your browser.
What's the difference between flattening and password-protecting?
Flattening removes interactivity; a password only restricts access. A password-protected PDF can be unlocked and its fields are still editable; a flattened PDF has no editable fields left at all. They solve different problems and can be combined.
Does flattening reduce the file size?
Not reliably — it can go either way. Removing lots of interactive elements can shrink a file slightly, but flatten-to-image can make it larger. If a smaller file is the goal, compress the PDF instead.
Can I flatten transparency for printing here?
No — that's a different, print-specific operation. Transparency flattening for professional print/prepress is done in Acrobat Pro or Illustrator. This tool flattens form fields and annotations to make a PDF read-only, not transparency for output.
Are my files uploaded to a server?
No — everything happens in your browser. Your PDF is flattened locally on your device and never uploaded, so no copy is left on any server. You can even flatten with your internet disconnected once the page has loaded.
Related PDF Tools
Flattening is often the last step before sending a document. These tools run in your browser too:
- Sign PDF — add a signature, then flatten to lock it
- Compress PDF — reduce the file size in MB for email and uploads
- Crop PDF — trim margins and white space before flattening
- Merge PDF — combine documents before locking them read-only
- Resize PDF — change the page size to A4, Letter, or custom
Ready to Flatten Your PDF?
Free, private, and permanent — make your form or contract read-only without your document ever leaving your device.
Flatten a PDF Now