A short workflow for anyone trying to send a long report or scanned bundle by email and running into an attachment-size warning. The plan is simple: compress the PDF as much as you can without hurting quality, then split it into parts only if compression alone cannot get you under the limit. Both tools run in your browser.
PDF splitter as a fallback if the file is still oversized after compression
Step-by-step instructions
Check the current file size in your file manager. If it is already under your recipient's attachment limit, no further work is needed.
Open the PDF compressor and drop in your file. Start with the lossless setting. This strips structural overhead and re-encodes object streams without changing any visible content.
Download the compressed file and look at its new size. If it is now under 25 MB you can stop here and attach it.
If the file is still too large, run the compressor again with the medium preset, which re-renders embedded images at a smaller footprint. Use the low preset only when you really need maximum shrinkage.
If even strong compression cannot get you under the limit, open the PDF splitterand drop in the compressed file. Choose "Split by page range" and divide the document into roughly equal parts that each fit under the cap.
Rename each part with a clear sequence label, for example "contract-part-1-of-3.pdf", and attach them to one or more emails. Mention the total number of parts in the email body so the recipient knows what to expect.
Expected output and how to verify
You should end with one PDF under your recipient's attachment limit, or with a small set of clearly labelled parts that each fit under the limit. Attach the file in your email client and watch for a size warning. If the client accepts it, you are good. Open one of the smaller parts to confirm the pages still render correctly and no content has been lost.
Common pitfalls
Going straight to the low compression preset can soften scanned text. Try lossless first and only step down if the size goal is still unmet.
Some email providers count the encoded attachment size, which is slightly larger than the raw file. Leave a megabyte or two of headroom under the official limit.
Splitting at random page boundaries can break the flow of a contract or report. Split between natural chapter or section breaks where possible.
Variations
If the recipient can accept a shared link instead of an attachment, upload the compressed PDF to a file-sharing service and send the link, which avoids all attachment limits. If your PDF is mostly text, consider extracting the text with the PDF text extractor and pasting it into the email body instead.
Frequently asked questions
Why is 25 MB the target?
Most major email providers cap inbound and outbound attachments around 25 MB. Some allow more on paid plans, but 25 MB is the safe upper bound that works for most senders and recipients.
What if the recipient uses a stricter limit?
Some corporate filters cap attachments at 10 MB or even 5 MB. If you know the recipient is on a tight limit, target that number in step three instead of 25 MB.
Does compression affect document quality?
Lossless compression removes structural overhead without touching content. Image-based compression modes re-render pages and reduce quality slightly. Pick lossless first, then escalate only if the size target is still missed.
Should I send a split PDF as separate emails?
Sending one part per email avoids attachment limits entirely. Name the files clearly (part-1-of-3, part-2-of-3, and so on) so the recipient knows the order and how many to expect.