Split PDF by size

To split a PDF by size, choose the largest size one file may be, upload the PDF, and download the ZIP. pdfly starts at page 1 and puts as many pages in the first file as fit under your limit. The next file starts where that one stopped. You get multiple files, every one at or under the size you picked, with the pages in their original order.

1. Pick a size per file. 10 MB opens selected because it suits most office mail. Choose Custom for any other number.
2. Drop the PDF on the tool and start the split.
3. Download the ZIP. Inside, the parts are numbered in page order, so part 1 holds the first pages.

Sizes are measured on the real files, not estimated. A font or an image used on many pages is copied into every part that shows it, so the parts can add up to a little more than the original. That is the price of each part opening on its own.

Most PDF splitters ask where to cut: every 10 pages, or pages 4 to 9. That works when you want a chapter. It is guesswork when the real rule is a number of megabytes, because one scanned page can weigh more than fifty pages of text.

pdfly works the other way round. You give the limit, and it finds the cut points. Use it when a mailbox, a form, or a portal rejects anything over a size. It does not extract a page range or save chosen pages on their own. For that, a page-based PDF divider is the right tool.

Sometimes a single page is over the limit by itself, usually a full-page photo or a high-resolution scan. Cutting cannot help there, so pdfly compresses that page alone until it fits. The pages around it are left as they are.

Rasterizing turns the page into a picture of itself. It can make a stubborn page much smaller, but the text on it may no longer be selectable, so it only runs when you tick the box. If the page still cannot get under the limit, pdfly tells you which page it was and the smallest size it reached. You get no ZIP rather than a part that breaks your limit.

If one smaller file is enough, compressing is simpler: the reader opens one document, not several. Use the PDF compressor and give it the same size. Splitting is the better choice when the file has to stay sharp, such as drawings, photos, or signed scans, or when even the smallest compressed copy is over the limit.

The two also combine. Compress first to see how small the file can get, then split what is left. If quality is the worry, Compress a PDF without losing quality explains which passes run first and when pages turn into pictures.

Email is the most common reason to split. Gmail and Yahoo Mail accept 25 MB per message and Outlook 20 MB, but attachments grow by about a third when they are sent, and the person you write to may sit behind a stricter office server. Pick a size under the smallest cap you know, and send one part per message. PDF too big to email covers the caps and the encoding overhead in detail.

On a Mac, Preview can split a PDF by hand. Open the sidebar, select page thumbnails, and drag them to the desktop to make a new file. It does not know your size limit, so you check each file in Finder and try again when one is too big.

pdfly runs in the browser, so it works the same in Safari or Chrome on macOS, with nothing to install. If you would rather keep one file and make it smaller, Compress a PDF on a Mac walks through Preview's filter and its limits.

Application forms, filing systems, and school portals often set a size per file and accept several files. Check the number on the form, pick it here, and upload the parts in order. If the form wants a single file, compress instead, or merge PDFs under a size limit when it wants several documents in one upload. Why is my PDF so large explains what made the file heavy in the first place.

You can upload a PDF up to 100 MB with up to 500 pages. One split returns at most 100 files; if it would need more, choose a larger size per file. The size per file can be anything from 8 KB to 100 MB. A password-protected PDF, or one pdfly cannot read, is rejected. A file already under your limit comes back as one part, unchanged. The upload and the ZIP are deleted within 1 hour, and there is no account to create.