Split PDF by File Size

Split PDF by File Size — Free & Private

When you need to send a large PDF by email or upload it to a service with strict size limits, breaking the document into smaller parts that each stay below a size threshold is essential. This free online PDF size splitter does exactly that, right inside your browser, with no uploads required.

How it works

1. Select a PDF file from your device.
2. Enter a maximum size in megabytes for each output part (for example, 5 for a 5 MB per part limit).
3. Click Split by size — the tool walks through the document page by page and starts a new output file each time adding the next page would exceed your size budget.
4. Download each part individually. File names are suffixed with -part-1.pdf, -part-2.pdf, etc.

Why split by size?

• Email attachment limits — Gmail caps attachments at 25 MB, Outlook at 20 MB, and many corporate mail servers allow even less.
• Chat and messaging apps — WhatsApp, Slack, Discord, and Teams all have different size limits for document uploads.
• Form uploads — Government portals, school submission forms, and job applications often reject files over 5 or 10 MB.
• Slow connections — Sending smaller chunks can be faster and more resilient on unreliable networks.

Tips

• The tool keeps pages intact. A single page that is already larger than your threshold will be emitted as its own part — consider running Compress PDF first for image-heavy documents.
• Parts are numbered in reading order so re-combining them with our Merge PDF tool always restores the original order.
• All processing happens locally. Nothing is uploaded — your PDF never leaves your browser.
• Works with PDFs of any length, on desktop and mobile alike.

Related tools

• Split PDF — split by page ranges instead of size.
• Compress PDF — shrink a PDF before splitting.
• Extract PDF Pages — pull specific pages out of a document.