Most PDF viewers let you view two pages on screen at once, but that is not the same as actually putting them side by side in a way you can share or print. Split-screen works for a quick look. It does not work when you need to hand something off to a colleague, print 30 pages, or review a document without juggling two windows the whole time.
What you actually want is a single PDF where each page already has both documents placed next to each other horizontally. One file, everything aligned, opens in any PDF viewer.
This guide walks you through doing that in under two minutes using a free tool that runs in your browser. Nothing to install, no account needed, and your files stay on your device the whole time.
Step-by-Step: Put Two PDF Pages Side by Side
Open the PDF merger tool
Head to the homepage. You will see two upload zones sitting side by side, one for each PDF.
Upload your first PDF
Drag and drop your first PDF into the left upload zone, or click to browse your files. Once loaded it shows the file name and page count.
Upload your second PDF
Same thing for the right zone. This is the document that will appear on the right side of every merged page.
Choose a page size option
Three options show up once both files are loaded. "Scale to fit" works best for most people. It matches both pages to the same height so the output looks clean. "Stretch to fill" forces each page into exactly half the width. "Use larger size" keeps original dimensions with no scaling.
Click Merge and download
Hit the Merge button. Everything processes in your browser in a few seconds. The merged PDF downloads automatically. Open it in any PDF viewer and you will see both documents side by side on every page.
Ready to try it?
Merge PDF Pages Side by SideWhich Page Size Option Should You Choose?
The tool offers three ways to handle pages when your two PDFs have different dimensions. Here's when to use each:
Scale to fit (recommended)
Both pages get scaled to the same height and then placed side by side. Aspect ratios stay intact so nothing looks stretched. Use this for most cases, especially document comparison or bilingual PDFs.
Stretch to fill
Each page is stretched to fill exactly half the width of the output page. This gives a perfectly symmetrical layout but can distort the content if the two PDFs have very different proportions.
Use larger size
No scaling is applied. Both pages appear at their original size and are placed next to each other. Good when you need pixel-accurate output and both PDFs are already the same size.
What does the merged PDF actually look like?
Each page in the output is wider than a normal page. The left half shows the corresponding page from your first PDF, the right half shows the same page number from your second PDF. If you scroll through a 10-page merged document, you are reading page 1 of both files together, then page 2 of both files together, and so on.
The output is a standard PDF. It opens in Adobe Reader, Preview on Mac, browser-based PDF viewers, and any other PDF software. You can print it, share it by email, or upload it to Google Drive like any other file.
On paper, it prints best in landscape orientation. Two A4 portrait pages placed side by side produce one A3 landscape page. Most printers handle this without any settings change if you set the paper orientation to landscape before printing.
Your files stay on your device
The tool reads your PDFs locally in the browser and writes the merged file directly to your downloads folder. At no point does your file travel over the internet. If you are working with anything confidential, there is nothing being uploaded.
How browser-based PDF processing works, and why it matters for privacyFrequently Asked Questions
Can I put two PDF pages side by side without Adobe Acrobat?
Yes. Adobe Acrobat can show two pages on screen at once but it does not actually merge them into a single page. This tool combines both PDFs into a new file where each page shows both documents side by side. No Adobe subscription needed.
What if my two PDFs have different page sizes?
The tool handles it automatically. Pick "Scale to fit" and both pages get scaled to the same height before being placed side by side, so nothing looks stretched or cropped. You can also try "Stretch to fill" or "Use larger size" depending on what you need.
What if my PDFs have different numbers of pages?
The tool works through both files page by page. When the shorter PDF runs out, the remaining pages from the longer one are placed on their side of the output with a blank white area on the other side. Nothing gets cut off.
Is the merged PDF readable on mobile?
Yes, though side-by-side pages are wider than a regular page, so you may need to zoom in on a phone screen. It works best in a desktop PDF viewer or when printed on landscape paper.
Does this work with password-protected PDFs?
No. Remove the password from your PDF first using your PDF viewer, then come back and run the merge.
How is this different from just opening two PDFs in split-screen?
Split-screen means managing two windows and manually keeping them in sync as you scroll. With this tool you get one merged PDF where both documents are already aligned page by page. You can scroll through the whole thing in one window, share it as a single file, or print it without any extra setup.