Split PDF into 25MB Parts
Use the Gmail 25MB preset to split large PDFs into attachment-ready parts while keeping page order.
No quality loss, page order preserved.
Email presets: Gmail 25MB, Outlook 20MB, Outlook.com 25MB, plus custom size.
Example: 38 MB PDF -> 2 parts under 20 MB (keeps page order).
How it works
Set limit
Choose Gmail, Outlook, Outlook.com, or a custom MB value.
Split
We generate parts that fit the limit.
Download
Get a zip of split PDFs.
Split to 25MB FAQ
When should I split instead of compress?
If compression cannot reach the limit without quality loss, splitting keeps every page intact. You can also try email-ready compression first.
Can I rejoin the parts later?
Yes. Each part is a normal PDF and can be merged later if needed. The organize tool can merge parts.
Gmail-sized PDF parts
Why split instead of compress
Some PDFs are already optimized or are mostly images, so compression alone cannot reach the limit without visible quality loss. Splitting keeps quality intact by distributing pages across multiple parts.
This approach works well for long reports and scan-heavy files where every page matters. Each part is still a valid PDF you can open and send.
How parts are created
PDFThin groups pages to keep each part under 25 MB while preserving order. We aim for predictable sizes with a safety margin so attachments stay under the cap.
You receive a ZIP file containing numbered parts. Each part is ready to attach, and the order is clear for recipients.
Sending parts by Gmail
Attach one or more parts per email depending on your message size. If you need to send several parts, label the subject with the part number for clarity.
If you want a single file instead, try the email-ready compression workflow first. It optimizes before splitting.
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Organize PDF
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Step-by-step workflow for Gmail 25MB and Outlook 20MB limits.
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