Split PDF by File Size - Free Online Browser Tool

Break a large PDF into separate files under a target size for email limits.

Email servers reject attachments above a few megabytes, and upload forms refuse them too. Splitting a document by page count does not solve that, because pages are wildly uneven in weight. This measures the actual output and starts a new file whenever the next page would push the current one past your limit.

This split pdf by file size utility runs completely inside your web browser. Your document is opened locally and processed on your own device using JavaScript and WebAssembly, so your file is never uploaded to any server. There is no signup, no watermark and no limit on how many documents you can handle.

  • 100% client-side - files never leave your device
  • Instant processing, no upload wait
  • Works on desktop, tablet and mobile
  • Free forever, no account required

Common next steps: Split PDF, Split Every N Pages, Compress PDF, Count Pages & Words.

How to Use the Split PDF by File Size Tool

Four steps, and the whole thing runs locally on your own device.

  1. Load the large PDF

    The document needs at least two pages for a split to mean anything.

  2. Pick the size ceiling

    Two megabytes works for almost every mailbox. One megabyte is the safe choice if you do not know who will receive it.

  3. Process and measure

    Pages are added one at a time and the file is re-serialised after each, so the size check uses the real number rather than an estimate.

  4. Download the bundle

    You get one PDF per part plus a text file listing how many pages and kilobytes each one holds.

Frequently Asked Questions

Why not just split every N pages?

Because page count is a poor proxy for size. A document of ten scanned photographs and a document of a hundred pages of text have wildly different weight per page, so equal page counts produce wildly unequal files. Measuring the output is the only reliable approach.

Is every part guaranteed to be under the limit?

Every part except the last. A single page that is already larger than your limit cannot be made smaller by splitting, so it becomes a part of its own and you should compress it instead.

What if the document fits in one part?

You get that one PDF back rather than a pointless one-file archive, so there is nothing to unpack.

Does splitting reduce quality?

No. Pages are copied unchanged, so a part is byte-for-byte the same content as the corresponding pages of the original.

Can I get a specific file size like exactly 2 MB?

Not exactly, and forcing it would mean recompressing. This only guarantees a ceiling. If you need a tighter number, compress the document first, then split it.