Will splitting reduce the quality of my PDF?

No. Pages are copied exactly as they are. Only a page that is bigger than your limit on its own is converted to an image, and only if you leave that option on.

Why are my parts smaller than 25MB when I chose Gmail?

Email encoding makes attachments about 37% bigger in transit, so each part is kept under about 18MB to arrive within Gmail's 25MB limit.

Can I choose where the PDF is split?

Not here - this tool cuts wherever the size limit requires. To split at chosen pages or every N pages, use Split PDF.

What happens to a page bigger than the limit?

It goes into its own part. If compression is on, that page is shrunk to fit; if it still cannot fit, the part is marked as over the limit.

No. The PDF is split in your browser and never leaves your device.

Split PDF by Size

Break a large PDF into parts that each stay under the size you need - for email attachments or upload portals. Every part is built and measured, so none goes over the limit.

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Is this the right split tool?

An email or upload limit per file

Choose the limit and every part stays under it.

One page is bigger than the limit

That page can be compressed on its own; anything still too big is clearly marked.

Splitting at chapters, chosen pages or every N pages

This tool cuts by size, not by page number.

Split by pages instead

One smaller file instead of several parts

Compress the PDF to a target size instead of splitting it.

Compress PDF to a size

Features

Presets for Gmail (25MB), Outlook (20MB) and common portal limits
Custom limit in KB or MB
Each part is measured, not estimated, so it really fits
Pages are copied as-is - no loss of quality
Optionally compresses a page that is too big on its own
Numbered parts (file-part-01.pdf...) and a single ZIP download

When to split by size

Email attachments

Send a scanned document that is too big for one email as several attachments.

Upload portals

Fit documents into portals that cap each file at 1MB, 2MB or 5MB.

Messaging apps

Share a large report in parts that open quickly on a phone.

How splitting by size works

Why Gmail's 25MB is not 25MB of PDF

Email attachments are encoded as text when sent, which makes them about a third larger. A 25MB limit therefore fits roughly 18MB of PDF. The Gmail and Outlook presets already allow for this, so the parts send without bouncing.

Where the cuts happen

The tool fits as many pages as possible into each part, in order, then starts the next one. You choose the size, not the page numbers. To split at specific pages or every few pages, use Split PDF instead.

When a single page is too big

A page bigger than the limit by itself cannot be split further. With "Compress pages that are too big" on, just that page is converted to a smaller image-based page.
If it still does not fit, it is marked in the list. Compress the whole PDF to a target size first, or choose a larger limit.
Need it back in one file later? Merge the parts.