PDF File Size Checker
Instantly see a PDF's exact size, page count, and whether it'll actually fit as an email attachment — not just whether it's under the advertised limit.
Drop a PDF here to check its size
How this tool checks email attachment limits
Email providers publish attachment size limits — 25 MB for Gmail, 20 MB for Outlook.com, and so on — but those numbers aren't the full picture. Attachments are encoded before they're sent, using a format that adds roughly a third to the file's actual size. A file that's 20 MB on your device can become close to 27 MB by the time it's packaged into an email, which is why files that look like they should fit sometimes bounce anyway.
This tool reads your PDF's exact size, page count, and password-protection status the moment you select it — no upload, no waiting — and checks it against both the advertised limit and the real, encoding-adjusted limit for each provider. A file gets marked "Fits" only when it's safely under that real limit; if it's under the advertised number but would likely fail once encoding overhead is added, it's flagged "Risky" instead of a false green checkmark. You can also check against any limit of your own — useful for services this tool doesn't track by default, like WhatsApp, Slack, or a specific limit your company sets.
Common use cases
- Checking a scanned document's size before attaching it to an email
- Deciding whether to compress a PDF before sending it, or send it as-is
- Confirming a PDF isn't password-protected before sending it somewhere that can't handle one
- Comparing a file against multiple providers when you're not sure which one your recipient uses
- Checking file size against a messaging app or internal policy limit that isn't a standard email provider
If a file doesn't fit, the Compress PDF tool on this site can shrink it — right in your browser, with no upload required there either.
Related tools
PDF File Size Checker — frequently asked questions
A file can be under a provider's advertised limit and still fail to send, because attachments are encoded before they're transmitted, which adds roughly a third to their size. 'Fits' means safely under that real, encoding-adjusted limit. 'Risky after encoding' means it's under the advertised number but likely to bounce once encoding overhead is added.
Email attachments are Base64-encoded before sending, which adds roughly 33-37% to the file's size. A 25 MB Gmail limit becomes about 18 MB of real, usable space — the effective limit is what actually determines whether a file goes through.
Yes — the custom limit field lets you type any number in MB and check against it, useful for services like WhatsApp or Slack, or a specific limit your company's IT policy sets.
Not guaranteed — the recipient's mail server may enforce its own, sometimes stricter, limit, and total message size includes any other attachments in the same email. Treat this as a strong guide, not an absolute guarantee.
No. The file size, page count, and password-protection status are all read directly in your browser — nothing is uploaded or processed on a server.
Use the Compress PDF tool on this site first to shrink it — also fully in-browser — or share it via a cloud storage link instead.