How does Split by File Size decide where to cut the PDF?

The tool measures the cumulative size of pages as it steps through the document. When adding the next page would cause the current part to exceed the target size, a new part begins at that page. This ensures every part stays under the limit while minimising the total number of parts.

What target size should I use for email attachments?

Most email providers allow up to 25 MB (Gmail, Outlook). To be safe — accounting for base64 encoding overhead in email — set the target to 19 MB for a 25 MB limit, or 7 MB for a 10 MB limit. This buffer ensures the encoded attachment stays within the provider's cap.

Can a single page be larger than my target size?

If a single page (such as a full-resolution photograph) is larger than the target size on its own, that page will form its own part that slightly exceeds the target. The tool cannot split a single page — it can only split at page boundaries.

How many parts will my PDF be split into?

The number of parts depends on the total file size and your target. A 90 MB file split at 9 MB will typically produce around 10 parts, though image density variation may affect the exact number. The tool shows you the result before you download.

Does splitting by size reduce image quality?

No. The tool groups pages into parts without re-encoding any content. Image quality, text sharpness, and all other PDF elements are preserved exactly as in the source.

What is the difference between Split by File Size and Split in Half?

Split by File Size targets a specific output size in megabytes and produces as many parts as needed. Split in Half always produces exactly two parts divided by page count at the midpoint. Use Split by File Size when you have a strict size constraint; use Split in Half when equal page distribution matters more.

Can I merge the parts back together?

Yes. Use dokk.ai's Merge PDF tool to recombine all parts in sequence once the recipient has downloaded them all, reconstructing the original document.

Should I compress my PDF before splitting it?

Often, yes. Running Compress PDF first can reduce the file size enough that splitting becomes unnecessary. If the compressed file is still too large, splitting it by size afterwards produces fewer, more manageable parts.

Is there a minimum target size I can set?

The minimum target size is 1 MB. Setting a very small target on a document with large pages may produce many parts, each containing only one or two pages. For very granular splitting, consider Split by Page Range for explicit control.

Are the output parts labelled so the recipient knows the order?

Yes. Output files are named sequentially — for example, 'document_part_01.pdf', 'document_part_02.pdf' — so recipients can reassemble or read them in the correct order without additional instructions.

Totes les eines

Divideix per mida

Divideix en fitxers per mida màxima

1Puja

2Configura

3Processa

Drop file here

PDF, Word, Excel, PowerPoint, images up to 25 MB

Característiques principals

Splits PDF into parts each under a user-defined file size limit
Content-aware page grouping that measures cumulative size dynamically
Sequential part numbering with consistent filenames
Downloads individual parts or a ZIP archive
Works with text-only and image-heavy PDFs
Preserves all content including images
fonts
and annotations
No page number input required
Handles PDFs up to 200 MB
Secure TLS upload and automatic deletion after 60 minutes
Browser-based with no installation required
Compatible with all email
portal
and storage size restrictions

Casos d'ús

Splitting a PDF to fit under a 10 MB or 25 MB email attachment limit
Breaking a large engineering drawing set for a file portal upload
Dividing a product catalogue into email-deliverable sections
Splitting legal case files for secure messaging within size limits
Preparing academic supplementary material for journal submission portals
Breaking oversized reports into chunks for a content management system
Splitting a large scanned archive into manageable file sizes
Dividing a high-resolution photo book PDF for cloud storage upload limits
Preparing government submission documents within portal constraints
Breaking large HR documentation packages into upload-ready portions

Com s'utilitza

1Upload the PDF you need to split. The tool displays the total file size and page count for reference.
2Enter the target maximum size in megabytes for each output part — for example, 9 MB to fit under a 10 MB email limit.
3Click Process. dokk.ai groups pages into parts, measuring cumulative file size as it goes, and cuts a new part whenever the next page would exceed the target.
4Review the list of generated parts showing the page range and file size of each.
5Download individual parts or click 'Download all as ZIP' to get every part in a single archive.

Most email providers cap attachments at 10 MB or 25 MB. Many cloud portals enforce a strict upload limit. SharePoint sites, government submission systems, and client portals all have their own maximums — and a 90 MB engineering report or product catalogue simply refuses to go through. Manually trial-and-erroring page ranges until each part is under the limit wastes time you do not have. Split by File Size takes a target size in megabytes and automatically divides your PDF into as many parts as needed, each guaranteed to stay under that limit. You enter '9 MB', click Process, and dokk.ai calculates and produces the required number of parts without you touching a single page number. The parts are numbered sequentially and can be downloaded individually or as a ZIP archive. The calculation accounts for real-world PDF structure. Page size in a PDF is not uniform — a page with a full-bleed photograph occupies far more space than a text-only page. The tool measures the cumulative size dynamically as it steps through pages, cutting a new part whenever the next page would push the current part over the target threshold. This means part boundaries are content-aware, not naively arithmetic. Use cases span every industry. Legal firms split case files into email-sendable portions. Architects distribute large drawing sets in installments. Academics submit supplementary material in parts when journal portals enforce limits. Recruiters split oversized application packets before uploading to HR systems. In each case, the recipient reassembles the parts in order — or you can merge them back together with dokk.ai's Merge PDF tool once the transfer is complete. For even smaller output files, run Compress PDF on the source document first before splitting — this often eliminates the need to split at all. If you need to divide at meaningful content boundaries rather than size thresholds, Split by Bookmarks or Split in Half may be more appropriate. All processing is encrypted in transit and files are deleted within 60 minutes, keeping confidential documents secure throughout.

Preguntes freqüents

Seguretat i privadesa

Your PDF is uploaded over TLS encryption. All uploaded and processed files are automatically deleted within 60 minutes. dokk.ai does not store document content or share files with third parties. GDPR compliant.