How to Send Several PDFs as One Attachment
The simplest way to send several PDFs as one attachment is to merge them into a single PDF, check that it's under your email's size limit, and attach that one file. With PDF Merge you add the files, put them in order, click Merge PDFs, and download one document called merged.pdf.
If the merged file is too big to email, you have two choices: make the source files smaller and merge again, or send a link instead of an attachment. Both are covered below.
Merge or zip?
There are two ways to turn several files into one attachment, and they're not the same:
- Merging joins the pages into one PDF. The person receiving it opens a single document and scrolls through everything in order. This is what people mean when a form or an office asks for "one PDF".
- Zipping packs the separate files into one .zip archive. It's still one attachment, but the recipient has to unzip it and open each file. Some upload portals and company email filters don't accept zip files.
If someone asked for one PDF, merge. If you're sending a mix of file types, such as a spreadsheet and a PDF, zipping may be the better fit.
How to merge your PDFs
- Open PDF Merge. Drop your PDF files onto the dashed box, or click it to choose them. You can select several at once and add more later.
- Check the list. Each file shows its name and size. Anything that isn't a PDF is skipped.
- Use the ↑ and ↓ buttons to set the order. The top file becomes the first pages of the new document.
- Remove anything added by mistake with the ✕ button on its row.
- Click Merge PDFs. It needs at least two files.
- Click Download merged.pdf.
- Open the file and scroll through it before you send it. It's the quickest way to catch a file in the wrong place.
Rename the merged file before attaching it. merged.pdf tells the recipient nothing; Ali-Khan-rental-application.pdf does.
The merge runs in your browser, so the files aren't uploaded to our server. That's useful because the documents people combine are often private: bank statements, payslips, ID scans.
Before you merge
- Number the file names, such as
01-form.pdf, 02-id.pdf, 03-payslips.pdf. It makes the order easy to check at a glance.
- Every page of every file is included. If you only need part of a document, export those pages from your PDF reader first. PDF Merge joins whole files; it doesn't split, rotate, or delete single pages.
- Remove passwords first. The tool can't open encrypted PDFs. Open the file in your PDF reader with the password, save an unprotected copy, and merge that.
- Convert images first. Photos and Word documents are ignored when you add them, so save them as PDFs beforehand. Most phones and office programs can do this through Print or Save as PDF.
Check the size before you send
Email services limit how big a message can be, and the limit includes everything attached. Microsoft's Outlook support page says the limit for many internet email accounts is 20 MB, and that Exchange business accounts default to 10 MB. Other providers set their own numbers, and a company's IT team can set lower ones. If you're not sure, staying under 10 MB is a safe target.
Email also makes attachments slightly bigger in transit, because files are encoded as text. A 19 MB PDF can fail against a 20 MB limit, so leave some room.
You can see the size of each file in the PDF Merge list. The merged file will be roughly their total.
If the merged PDF is too big
Scanned pages and photos are almost always the cause. A text document exported from Word might be a few hundred kilobytes; one page scanned at high resolution can be several megabytes. Ways to bring it down:
- Rescan at a lower resolution. For documents, 150 to 200 DPI is usually enough to read clearly. (DPI, dots per inch, is how much detail a scanner captures; higher means bigger files.) Choose greyscale instead of colour for text-only pages.
- Shrink photos before making them into PDFs. If you photographed documents with your phone, run each image through Image Compress first. Choose JPEG, set Max width to around 1500 to 2000 pixels, and keep quality at about 80%. Then convert the smaller images to PDF and merge.
- Trim the edges. Cropping away table and background around a photographed page with Image Crop makes it easier to read and slightly smaller.
- Use your PDF reader's reduce-size feature if it has one. Many desktop PDF apps offer an option to reduce or optimise file size.
After making the sources smaller, add them to PDF Merge again and run a new merge. The download button always gives you the last merge you ran.
Or send a link instead
If the file has to stay large, for example a long scanned contract, upload it to a cloud storage service such as OneDrive, Google Drive, Dropbox or iCloud and paste the share link into your email. Microsoft suggests the same approach for files over the attachment limit. Set the link so only the people you send it to can open it, especially for personal documents, and remove the share once they've downloaded it.
If the recipient insists on an attachment or a single upload, go back to the size-reduction steps above.
Need to sign it first?
If one of the pages needs your signature, sign that PDF with PDF Sign before merging, or sign the merged file afterwards. To type a date or a reference number onto a page, use Add Text to PDF.
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