mergepdfs.dev
Free PDF merger · runs in your browser

Merge PDF files free. No sign-up, no limits.

Combine PDFs online in a few seconds: add your files, put them in order, download one PDF. A free PDF combiner with no watermark and no account, and your documents never leave your device.

  • Free
  • No watermark
  • No sign-up
  • Files stay on your device
  • No file limits
  • Works offline

A free PDF combiner that keeps your files private

  • FreeMerge as often as you like. No trial, no paywall.
  • No watermarkYour merged PDF carries no logo or stamp.
  • No sign-upNo account, no email, no installs.
  • Files stay on your deviceMerging happens in your browser. Nothing is uploaded.
  • No file limitsAny number of files and pages your device can hold.
  • Works offlineOnce the page has loaded, merging needs no connection.

How to merge PDF files

  1. 01

    Add your PDFs

    Click the box above or drop files onto it. Add more at any time, from any folder.

  2. 02

    Put them in order

    Drag the cards, or use the arrows. Rotate a file that's sideways, remove one you don't need.

  3. 03

    Fine-tune (optional)

    Open Organize pages to move, turn or delete single pages, or Match page sizes to make every page A4 or Letter.

  4. 04

    Merge and download

    Name the file and press Merge and download. The combined PDF is saved straight to your device.

Why your files never leave your device

Most online PDF tools upload your documents to their servers, process them there and ask you to trust that they delete them afterwards. This merger works the other way round: the page brings the PDF engine to you. Your browser reads the files, builds the merged PDF and saves it, so statements, contracts and IDs stay on your computer or phone.

  • No upload, so no waiting for big files to transfer
  • No copy of your documents on anyone's server
  • Passwords for locked files are used on your device only
  • Keeps working if your connection drops mid-way

What people combine

Paperwork in one file

Bank statements, receipts and invoices for a month or a tax year, sent as a single attachment.

Job and school applications

Cover letter, CV, certificates and references in the order the form asks for.

Reports and theses

Chapters written as separate documents, plus a title page and appendices.

Scans from your phone

Pages scanned one at a time, joined into one document and turned the right way up.

Contracts and signatures

A signed page put back into the original agreement, without re-sending the whole thing.

Print-ready packs

Mixed Letter and A4 handouts made the same size so they print cleanly.

Questions about merging PDFs

Is it really free to merge PDF files here?

Yes. Merging PDFs in your browser is free with no sign-up, no watermark and no limits, and it stays that way. Credits only exist for the developer API, which merges files on our servers.

Is there a limit on the number of files or the file size?

No. The merger has no file or page limit of its own: you can merge PDF files of any size and number that your device's memory can handle. Very large jobs (hundreds of megabytes) are smoother on a computer than on an older phone. The API, which runs on our servers, takes up to 20 files and 100 MB per merge.

Are my files uploaded anywhere?

No. Your PDFs are read, previewed and merged by your own browser, and the result is saved straight to your device. They are never uploaded to us or to anyone else, and the page makes no network requests while it merges.

Will the merged PDF have a watermark?

No. There's no watermark, stamp, cover page or extra blank page. The file contains your pages and nothing else.

Can I merge password-protected PDFs?

Yes, if you know the password. A locked file shows a password box on its card; the file is unlocked on your device and the password is never sent anywhere. Files that only restrict printing or copying open without asking. The merged PDF has no password.

How do I change the order of the files or pages?

Drag the file cards, or use the up and down arrows (they work with the keyboard too). To move single pages, even between files, open Organize pages, where you can also rotate or delete pages and restore them.

Does it work on a phone or tablet?

Yes. The merger works in current mobile browsers on iPhone, iPad and Android. Pick files from your Files app or downloads, drag cards by their handle, and the merged PDF lands in your downloads.

My PDFs have different page sizes. What happens?

By default every page keeps its own size, and the merger warns you when sizes are mixed. Open Match page sizes to give every page the same size (the first page's, A4, Letter, Legal, A3, A5, Tabloid or a custom size), with fit or fill scaling and an optional margin.

For developers

The merge API

Merge PDFs from your own app, script or no-code workflow with one request. Send the files (or their URLs) in order and get the merged PDF back. 1 credit per successful merge, from 1.56¢ with the Pro pack. Failed merges are free.

Upload files
curl -X POST https://mergepdfs.dev/v1/merge \
  -H "x-api-key: mpdf_…" \
  -F "files[]=@cover.pdf" \
  -F "files[]=@report.pdf" \
  -F "output_name=report-final.pdf" \
  -o report-final.pdf
From URLs, resized to A4
curl -X POST https://mergepdfs.dev/v1/merge \
  -H "x-api-key: mpdf_…" \
  -H "Content-Type: application/json" \
  -d '{
    "urls": ["https://example.com/a.pdf", "https://example.com/b.pdf"],
    "pages": ["1-3", ""],
    "page_size": "a4",
    "scaling": "fit",
    "margin": 10
  }' \
  -o merged.pdf
ParameterDescription
files[]PDF files in merge order (multipart). Up to 20 files, 100 MB in total.
urlsInstead of files: public http(s) PDF URLs in order (JSON). An entry can be { "url", "pages" }.
pagesOne page selection per file, e.g. ["1-3,5", "", "2-"]. Empty means every page; "5-3" reverses.
output_nameFile name of the result (default merged.pdf).
page_sizekeep (default), first, a4, letter, legal, a3, a5, tabloid or custom (with width and height).
orientationauto (default: the sheet turns with each page), portrait or landscape.
scalingfit (default: whole page, blank space where shapes differ) or fill (edge to edge, trims overflow).
margin, unitMargin on every side; unit is mm (default) or in, also used for custom width and height.
  • Response. The merged PDF (application/pdf) with X-Pages, X-Merge-Id, X-Credits-Remaining and X-Job-Id. If the merge takes longer than about a minute you get 202 with status_url (GET /v1/jobs/:id) and result_url (GET /v1/jobs/:id/result).
  • Errors. 401 missing or revoked key, 402 out of credits, 413 over 100 MB, 422 a file is unreadable or password-protected (or a page selection doesn't exist), 400 bad parameters or URLs. None of these use credits.
  • Privacy. API files are processed on our servers and stored privately in your account, unlike the browser merger above, which never uploads anything.
Get an API keySee pricing