Your file is too big for email. Here's how to send it.
Workarounds for Gmail, Outlook, and the rest · Updated May 2026
Most email caps attachments at 20 to 25 MB. sto.care lifts that to 5 GB. Drag a file, paste an email, get a link you can send through any inbox.
- 5 GB per file, well above any inbox cap
- No signup, send through any email client
- 7-day auto-expiry, with a one-click revoke link
- Free, no ads on the download page
Why the cap existsWhy email caps attachments where it does
SMTP, the protocol every mail server still speaks, was finalised in 1982 when a fast modem moved 1.2 kilobits per second. The polite attachment ceiling settled around 10 MB and has barely budged since, because every gigabyte that flows through an inbox has to be stored, scanned, and indexed for search. The second factor is encoding: email can't carry binary bytes natively, so attachments are wrapped in Base64, which turns every 3 bytes of file into 4 bytes of text. That's roughly a 33% inflation, documented in Microsoft's own Exchange size-limits guide. A 19 MB file on disk becomes a ~25 MB encoded message, which is exactly why Gmail's 25 MB ceiling translates to a real ~19 MB raw-file budget. The numbers below are encoded ceilings; subtract about a quarter to get the file size you can actually attach.
Gmail's 25 MB cap is from Google's support docs. Microsoft's figures are pulled from the Exchange Online limits service description. If your work account rejects an attachment well under those numbers, your IT admin set a tighter custom limit; the org policy beats the default every time.
Three stepsHow to send a file too big for email through sto.care
- Drag the file onto sto.care. The browser uploads it directly to AWS S3 over TLS, in multipart chunks. Up to 5 GB. No app to install.
- Enter your email and the recipient's. Yours so we can send you the revoke link. Theirs so the download notification reaches them.
- We mail you a link, you forward or paste it. The recipient gets a download URL in their inbox, or copy it from your confirmation email and drop it into Slack, WhatsApp, Signal, wherever.
Trade-offsWhen to use sto.care instead of the other workarounds
Gmail silently swaps large attachments for Google Drive links if you're signed in. Outlook offers OneDrive links for files over its cap. WeTransfer is the classic non-account workaround. Dropbox Transfer is the paid-tier route. None are wrong, they just optimise for different things.
Drive and OneDrive win when the file should live somewhere permanently with version history. Dropbox Transfer fits if you already pay for Dropbox. WeTransfer is faster for casual one-off sends if you don't mind a 3 GB ceiling and no recall. sto.care fits the one-shot send where you don't want a permanent copy in someone else's account, where you might want to revoke the link an hour later, and where neither side wants to make an account.
The fine printWhat we are and aren't
We aren't end-to-end encrypted. Files travel over TLS and S3 encrypts them at rest with AES-256 server-side keys; AWS holds the keys, so we could technically decrypt a file if compelled to. If that's a concern, an E2EE tool like Wormhole or Tresorit Send fits better. We aren't for permanent storage either: after 7 days the object is gone, the link 404s, no Trash. The 5 GB ceiling, 10 uploads-per-hour-per-IP rate limit, and fixed 7-day window keep the bandwidth bill predictable enough that we don't need a paid tier.
FAQCommon questions
What's the actual file size limit on Gmail?
Gmail caps personal-account attachments at 25 MB. That figure is the size of the encoded message, not the raw file. Email attachments are wrapped in Base64, which inflates them by roughly 33%, so a 19 MB file from your disk hits the 25 MB cap once Gmail finishes encoding it. Anything larger gets converted to a Google Drive link automatically. Source: Google support article, support.google.com/mail/answer/6584.
Why does Outlook tell me my attachment is too large at 10 MB when the limit is 20 MB?
Because there isn't one Outlook limit, there are several. On-premises Exchange Server defaults to 10 MB for send and receive. Microsoft 365 mailboxes default to 35 MB send / 36 MB receive (configurable up to 150 MB). Outlook on the web caps at 112 MB. Mobile Outlook caps at 33 MB. If your IT admin tightened the org policy you'll hit a number well below any default. Source: Microsoft Learn, Exchange Online limits service description.
Can I just zip the file to make it smaller?
Sometimes, mostly for documents and source code. Zip uses DEFLATE compression, which already-compressed formats (JPEG, MP4, MOV, MP3, PDFs wrapping JPEGs) won't shrink in any meaningful way. A 40 MB raw photo zips to about 39.8 MB. A 200 MB MP4 zips to about 199 MB. Text-heavy files (CSV, JSON, source) can see 60 to 90% reductions. For media, zip is theatre.
Is sto.care free for email replacement use?
Yes. 5 GB per file, no signup, no credit card, no "upgrade to send larger files" prompt. The recipient downloads in their browser, no account required on their end either. The only limits are 10 transfers per hour per IP and a fixed 7-day window before the file auto-deletes.
Will the recipient see ads or upsell when they download?
No. The download page is a single button on a plain layout. No interstitial, no "Try Pro free" banner, no email capture, no countdown. We don't run a paid tier, so there's nothing to upsell them on.
How do I take back a file once I've sent it?
When the upload finishes we email you a confirmation at the address you put on the form. That email contains a one-click revoke link. Click it once and the object is purged out of S3 immediately, even if the recipient is mid-download. Their connection drops and the link 404s on the next try.
Stop fighting the 25 MB cap. Send the file.
UPLOAD A FILE →Want the longer version per provider? See our deep dives on the Gmail attachment limit and the Outlook attachment limit. If you're weighing sto.care against a Google Drive link, read sto.care vs Google Drive. For every transfer-ceiling number on one screen, see send large files free.