Email Attachment Too Big? Every Fix, From Small to Huge

Updated 30 October 2026 · by the My Gadgets team

When an email refuses your attachment, there are only three real fixes: make the file smaller, send less of it, or send a link instead of the file. Which one is right depends on what you are sending. Photos and scanned PDFs usually shrink by 80 per cent or more with no visible loss; videos shrink a lot if you lower their resolution; anything over about 100 MB belongs in a cloud link, not an email. This article walks through each case, starting with the limit itself, which is smaller than most people think.

Why your 20 MB file doesn't fit a 25 MB limit

Email was designed for text, so attachments are converted into text before they are sent. That encoding makes them about a third larger. A 20 MB file becomes roughly 27 MB inside the message, and fails a 25 MB limit.

As a rule of thumb, your attachments can total about three quarters of the advertised limit. At the time of writing, the common limits are:

The recipient's limit matters too. A message you can send may still bounce at a company whose server accepts only 10 MB.

Find your case

Photos: resize, then compress

A phone photo is usually 4000 pixels or more across and 3–5 MB. Nobody viewing it in an email needs more than about 2000 pixels.

1. Open the photo in Resize Image and set the width to 2000 (or 1600 for casual sharing), leaving the aspect ratio locked.
2. If it is still large, run it through Compress Image as JPG at quality 80.

Ten photos that were 40 MB together typically end up around 5 MB. Resizing is the step that does most of the work; lowering quality on a full-size photo saves far less. Both tools take a whole set at once: choose all the photos, set the width or quality for the first, and one button does the rest and hands back a single ZIP.

If the photos are iPhone HEIC files, convert them with HEIC to JPG first so the recipient can open them on any device; it converts several at once, too.

PDFs: it depends on what is inside

Try selecting a word in the PDF.

If you can't, the pages are images — a scan or phone photos — and that is why the file is large. Run it through Compress PDF on Standard: it re-encodes the images at a sensible resolution and leaves everything else alone, which often cuts a scan by 70–90 per cent. For a tight limit, use Aggressive or Maximum from the original. The full method, including a fallback for files it can't shrink, is in why is my PDF so large.

If you can, it's a text PDF, and text is cheap. The weight is in the pictures, or simply in the number of pages. Send only what the recipient needs with Split PDF or Remove Pages from PDF — the signed page, not the whole 60-page contract.

Videos: lower the resolution

Video is the one file type that is almost always too big for email. A minute of phone video is commonly 100–200 MB.

Open it in Compress Video and choose 720p. For a clip that will be watched on a phone or laptop, 720p looks fine and is often a fifth to a tenth of the original size. Trim anything you don't need first with Trim Video: every second you cut is a second you don't have to compress.

Even compressed, a video longer than a minute or two is usually still too big for email. That is where a link is the honest answer.

Several files: does zipping help?

Zipping bundles files into one attachment; it does not make photos, videos or PDFs smaller. Those formats are already compressed, so a ZIP of them is about the same size as the files themselves. ZIP compression helps with text, spreadsheets and other uncompressed documents.

Zip Creator is useful for the bundling part — one attachment instead of fifteen — and it compresses whatever can be compressed, so a folder of spreadsheets or text files often shrinks a lot. Shrink photos and PDFs first using the steps above, then zip the results.

Splitting a file into parts: only as a last resort

You can cut a large file into numbered parts with File Splitter, send each part in its own email, and have the recipient rejoin them with File Merger. It works, and the rejoined file is identical to the original. But it asks a lot of the recipient: they need every part, the joining tool, and some patience. Use it only when a link is not an option, and tell them how to rejoin the parts in the first email.

When to send a link instead

For anything above about 100 MB, or any video longer than a couple of minutes, upload it to cloud storage you already use and send the link. Gmail and Outlook do this for you, offering Google Drive or OneDrive when an attachment is too large.

Two things to get right:

• Set the sharing permission to the people who need it, not "anyone with the link", for anything private.
• For sensitive documents, encrypt the file before uploading it with Encrypt File, and send the password by a different route, such as a text message. The recipient opens it with Decrypt File.

Quick answers

Why did my email say the attachment was too big when the file is smaller than the limit? The encoding overhead: files grow by about a third when attached. Aim for three quarters of the limit.

Can I compress a Word or Excel file? They are already compressed internally (they are ZIP files underneath). If one is large, it usually contains large images; replace them with smaller versions inside the document.

Is it safe to shrink documents online? The tools linked here run in your browser, so your files are not uploaded anywhere while you shrink them. Only the email you send carries them.

What's the fastest fix for one too-large photo? Resize Image to 2000 pixels wide. It is usually the only step you need.

What to do next

Match your file to the table above: Resize Image and Compress Image for photos, Compress PDF for scans (its rebuild method for stubborn ones), Compress Video for clips, and a cloud link for anything really large. If you are preparing documents for an application portal rather than an email, the online application checklist covers the extra rules portals add.