Your 90MB PDF won't go through Gmail's 25MB attachment limit. Splitting it into roughly-equal parts under 25MB each is the simplest fix — your recipient downloads three attachments and is reading in two minutes.
Flint sizes splits to your limit automatically.
Set the size, Flint figures out the splits
Open split PDF, drop your file, choose 'split by size', enter '25' for MB. Flint walks through the document and breaks at page boundaries that keep each output under your cap. Most splits will be slightly smaller than the limit (page boundaries don't perfectly land on byte boundaries). You'll typically get 3-4 files from a 90MB source.
Try compression first
Before splitting, check if compression gets you under the limit in one file. A 90MB PDF with scanned images often compresses to 20-30MB without visible quality loss. If compression alone solves it, you don't need to split. If you still need to split after, splits are smaller.
Email vs portal limits
Gmail/Outlook attachment limits are usually 20-25MB. Many portals cap uploads at 10MB, 50MB, or 100MB. Match Flint's target to your real ceiling. Aim a couple MB below to be safe — some systems calculate base64-encoded size, which inflates by ~33%.
Reassembly on the recipient end
Send your splits with clear filenames ('Report-Part-1-of-4.pdf', etc.) and let the recipient merge them back if they need a single file. Flint's free merge handles this in one step.
FAQ
Are output files all the same size?
Roughly. Each is under your cap, but they'll vary because page sizes (in bytes) aren't uniform.
What if a single page is bigger than the size limit?
Flint warns you. A single 30MB page can't be split further without re-rendering. Compress that page or accept the oversize.
Does this affect quality?
No. Splitting is lossless. Pages aren't re-rendered. Compression is a separate, optional step.
Can I combine this with range-based splits?
Not in one operation, but you can range-split first, then size-split any oversize result.
Set a size, get email-friendly PDFs. Split by file size.