Altto
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Free · No sign-up · Runs in your browser

Merge PDF files into one, free

Add one or more PDFs, then drag, reverse, rotate or remove any page — right down to individual pages, not just whole files — and get back a single PDF, without a page ever leaving your device.

Not uploaded — nobody sees it Combine as many PDFs as you like No watermark, ever No subscription or account

Several page jobs to do? Organise PDF lets you reorder, rotate, delete, split, merge and number pages on one screen.

Your PDFs are never uploaded — they’re processed right here in this browser tab, on your device. They never reach a server, so we never see them, copy them or keep them.

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At a glance

Merge PDF: quick facts

Combine any number of PDFs into one file.

Updated

Price
Free. No sign-up, no watermark.
Pages
Drag any page into place, rotate or remove single pages, or reverse the order.
Quality
Pages are copied exactly as they are.
Works on
Computers and phones, in the browser.
Input
PDFs only. Unlock password-protected PDFs first.
Privacy
Your files are merged in your browser and never uploaded.
How it works

How to merge PDF files into one

Every page of every PDF you add lands in one grid, so you can sort, turn and trim the whole document before a single merged file is built.

  1. 01

    Add your PDFs

    Drop in two or more PDF files. They'll be added in the order you drop or select them.

  2. 02

    Set the order

    Every page from every file lands in one visual grid — drag any page into a new position, rotate it, or remove it individually before merging.

  3. 03

    Save your PDF

    Get back a single PDF with every page from every file, ready to share or print.

Tips

Tips for a tidy merged PDF

A few habits that save you redoing a merge after you’ve downloaded it.

  • Number your files before you add themFiles go into the grid in the order you pick or drop them. Renaming them 01, 02, 03 first means most of the order is right before you touch a single page.
  • Look for the one sideways pagePhone scans and photocopies often have a single page turned the wrong way. Rotate just that page in the grid instead of fixing the whole file afterwards.
  • Drop blank and repeated pagesScanners often add an empty back page, and forwarded paperwork repeats cover sheets. Remove them before merging so the finished file is shorter and easier to read.
  • Too big to email? Compress it afterwardsMerging keeps every page exactly as it was, so the result is roughly the size of all your files added together. If it won’t attach, run it through Compress PDF.

Like every Altto tool, this runs on your device — nothing you add is uploaded. How Altto works

25 MB

is the largest attachment Gmail will send. A merged PDF weighs about the same as all its parts together, so add up the sizes before you hit send.

Guide

Merging PDFs: other ways, and what to know

Ways to do this without Altto too, on Windows, Mac and phones, and the things that trip people up.

How to merge PDFs on a Mac

macOS has two built-in ways, and both are free.

From Finder (quickest)

  1. Select the PDFs in Finder.
  2. Control-click (or right-click) the selection.
  3. Choose Quick Actions → Create PDF.

Apple says the files appear in the order you select them, and the new PDF is named after the first one. Click them one at a time, in order, rather than dragging a box around them.

With Preview (more control)

  1. Open the first PDF in Preview and choose View → Thumbnails.
  2. Drag another PDF from Finder into the thumbnail sidebar, or drag individual page thumbnails across from a second Preview window.
  3. Drag thumbnails up and down to reorder them.

One catch: Preview saves changes to the open document automatically, so make a copy of the first file before you start if you want to keep it as it was.

How to combine PDFs on iPhone or iPad

  1. Open the Files app and go to the folder with your PDFs.
  2. Tap More (the circle with three dots), then Select, and tap each PDF.
  3. Tap More at the bottom right and choose Create PDF.

The combined PDF appears in the same folder, and your originals are left alone. The files are combined in the order they’re listed in the folder (normally by name), so the simplest way to control the order is to rename them first — 1 CV, 2 Cover letter, 3 References. If you’d rather drag pages into place, Merge PDF works in Safari too.

How to merge PDFs on Windows

Windows doesn’t include a way to merge PDFs. Microsoft Print to PDF, the built-in “printer” that saves PDFs, handles one document at a time, so it can’t combine files. Your options are a paid PDF editor such as Adobe Acrobat, an online merging service (most of which upload your files to their servers), or a tool that runs in the browser itself, like Merge PDF.

How to merge PDFs on Android

Android doesn’t have a standard built-in merge option either, and what’s available varies by phone maker. The browser method works the same in Chrome on Android as on a computer: open the tool, tap to add your PDFs from your phone’s storage or Google Drive, arrange them, and save.

Built-in ways to merge PDFs, by device
DeviceBuilt-in optionControl over page order
MacFinder Quick Action, or PreviewGood in Preview; by selection order in Finder
iPhone / iPadFiles app → Create PDFFiles only, in the order listed
WindowsNone—
AndroidNone as standard—
Any (browser)Altto Merge PDFPage by page, with rotate and remove

Before you merge: get the order right

The merge itself takes seconds. What makes the result look professional is five minutes of tidying first:

  • Decide what goes first. Whoever opens the file sees page one. For an application that’s usually the cover letter or CV; for an expenses claim, a summary sheet.
  • Number your filenames. Starting names with 01, 02, 03 keeps them in order in every file browser and every merging tool.
  • Look for sideways pages. Phone scans often come out rotated. Fix them now so nobody has to turn their head.
  • Drop the dead weight. Blank backs of double-sided scans, duplicate pages and fax cover sheets make the file longer and bigger.
  • Check any size limit. A merged file is roughly the size of all its parts added together. If it’s going to an upload form or an email, see how to compress a PDF afterwards.

Things that can trip you up

Password-protected PDFs. A locked PDF can’t be merged until the password is removed. If you know it, Unlock PDF takes it off, then you can merge as normal.

Photos and screenshots. Merging tools combine PDFs, not images. If some of your pages are JPGs or PNGs, turn them into a PDF first with Image to PDF — our guide on converting JPG to PDF explains how — then merge that file with the rest.

Needing to undo it later. Merging isn’t a one-way street. If you need a section back out, you can split the PDF again by page range.

FAQ

Frequently asked questions

What the merge tool can and can’t do. New to this? Our guide on how to merge PDF files also covers doing it on Windows, Mac and phones.

How many PDFs can I merge at once?
As many as you like. Add two files or twenty — they'll all be combined into a single PDF in the order you added them.
Can I remove just one page instead of a whole file?
Yes. Every page has its own remove button in the grid, so you can drop a single page — a blank scan, a cover sheet you don't need — without leaving the rest of that file out.
Can I choose the order the files are merged in?
Yes — and not just by file. Every page from every file you add lands in one grid, so you can drag any individual page into a new position, not only reorder whole files.
Can I reverse the page order of a PDF?
Yes. Add the PDF (or several) and press Reverse order above the page thumbnails: the last page becomes the first. That fixes documents that were scanned from the back of the pile. Press it again to undo, or drag pages to fine-tune the order, then save. With a single file this works as a “reverse PDF” tool.
Will merging affect the quality or formatting of my PDFs?
No. Each page is copied exactly as it is in the source file, so text, images and layout come through unchanged — you just get them back as one file instead of several.
Can I rotate a file before merging it?
Yes, page by page. Click the rotate icon on any page in the grid to turn just that page 90° at a time — useful if only one page in a scan came in sideways, not the whole file.
Can I merge a password-protected PDF?
Not directly — a locked PDF needs to be unlocked first. Use our Unlock PDF tool to remove the password, then merge it here.
Can I merge PDFs on my phone?
Yes. It works in phone browsers such as Safari and Chrome: pick the files from your Files app or downloads, sort the pages in the grid, and the merged PDF is saved to your phone. Very large files take longer on a phone, because the phone is doing all of the work itself.
Can I combine photos or Word files with my PDFs?
Not in one step — this tool only accepts PDFs. Turn photos into a PDF first with Image to PDF, or a Word document with Word to PDF, then add the result here alongside your other PDFs.
How do I merge only some pages from each file?
Add every file, then remove the pages you don’t want from the grid before you save. If you only need a few pages from one big file, you can also pull them out first with Extract PDF Pages and merge the smaller file.
How do I merge PDF files for free?
Open a free browser tool like Altto’s Merge PDF, add your files, arrange the pages and save one combined PDF. On a Mac you can also use Finder’s Create PDF quick action or Preview, and on an iPhone the Files app’s Create PDF option.
How do I combine PDFs on Windows without Adobe?
Windows has no built-in PDF merge feature, so use a browser-based tool. Altto’s Merge PDF runs in Edge, Chrome or Firefox, needs no install or account, and combines the files on your own computer without uploading them.
Can I change the order of pages when merging PDFs?
Yes. In Altto’s Merge PDF every page from every file appears in one grid, so you can drag individual pages into any position, rotate them, or remove single pages before you save.
Can I merge a PDF with a JPG or other image?
Not directly, because PDF merging tools combine PDFs. Convert the image to a PDF first with Altto’s Image to PDF tool, then merge it with your other files.
Can I merge PDFs without uploading them?
Yes. Altto’s Merge PDF joins your files inside your browser, so they are never sent to a server. The page loads the code, then your own device does the work. You can check this in your browser’s Network tab, as described on the About page.
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