ZIP for Email — Stay Under Attachment Limits

This tool fits the moment just before you hit send: you have several files to attach and you are not sure they will clear the recipient's mailbox. Instead of attaching, getting a bounce, and re-doing it, you bundle everything into one ZIP, pick the provider, and see a clear pass or fail against that provider's attachment ceiling before the email ever leaves your outbox.

It suits sending a batch of photos or scans to a colleague, a few project files to someone on Outlook, or a folder of paperwork as one attachment, and because system junk is left out, the bundle looks tidy to clients.

It is aimed at email specifically, not at large-scale distribution. If your material genuinely runs to hundreds of megabytes or more, a shared link from cloud storage is the better answer, and this tool will tell you when you have crossed that line rather than pretend otherwise.

Drop or select your files into the upload area; files dropped as a folder are added individually. The tool warns above 200 MB in total. Choose Gmail, Outlook, or Yahoo Mail from the presets, or pick Custom and type your own megabyte limit if your workplace mailbox is stricter. Optionally rename the output; it defaults to email-attachment.zip. Then create the archive.

Under the hood it builds a single ZIP at maximum compression with every file at the top level, leaves out common system junk (.DS_Store, __MACOSX, ._ files, Thumbs.db, desktop.ini), and numbers any files that share a name so none is overwritten. The finished file downloads to your device automatically, and a readiness summary appears: green with the final size when you are under the limit, red with Too large and a link to the Split ZIP tool when you are over. Switching provider clears the verdict until you create the ZIP again.

Everything runs in your browser. On this site, files are not uploaded to a server and nothing persists once the tab closes. Note what it does not do: it does not split files for you, does not add password protection, does not email anything, and the provider limits it checks are built-in defaults, not a live query of your account. An existing ZIP you add is packed inside the new one as a single file.

The biggest misconception is that zipping makes big attachments small. JPG and PNG photos, MP4 video, MP3 audio, PDFs and Office documents are already compressed, so a ZIP of them is barely smaller than the files themselves. The tool warns when such files are present. If the result is still too large, the fix is to send fewer files, shrink the files themselves (Compress Image or Compress PDF, for example), split the ZIP, or share a cloud link.

The attachment limits are provider defaults. Corporate Exchange mailboxes, paid plans, and individual admin settings vary, and email encodes attachments for sending, which some providers count and which adds about a third to the size. If your real ceiling is lower than the preset, use Custom and set it deliberately rather than trusting Gmail's 25 MB blindly.

Also: the 200 MB warning is about browser memory, not email; re-running cannot shrink an oversized ZIP; and the download starts as soon as the ZIP is ready.

Confirm the readiness banner is green and the stated size sits comfortably under the limit for the provider you will actually use, not just the one you happened to click. Open the downloaded ZIP and verify every file you intended is present and named correctly, since a clean-looking bundle can still be missing a file you forgot to add. If the banner is red, follow the Split ZIP link or move to a shared link instead of attaching anyway.

Leave headroom under the cap rather than landing on the exact number, because of that encoding overhead: a file at 24.9 MB can still bounce from a 25 MB mailbox. If you renamed the attachment, make sure the name reads sensibly to the recipient and still ends in .zip.

For official or financial emails, extract the ZIP yourself and open the key documents; the size check cannot tell you they are the right files.