How to get a video under 10 MB

"The file is too large to attach" is the most unhelpful error message on the internet. The fix depends entirely on which limit you are hitting, so start by knowing the ceiling.

Attachment limits worth knowing

• Discord (free) — 10 MB. The tightest common limit, and the reason this is the number people search for.
• WhatsApp — 16 MB as a photo or video attachment, but 2 GB if you send the file as a document instead. That distinction is the single easiest way around the whole problem.
• Gmail — 25 MB per message, and base64 encoding inflates an attachment by roughly a third, so treat 18–20 MB as the real practical ceiling.
• Outlook / Microsoft 365 — 20 MB by default, sometimes raised to 34 MB or 150 MB by an administrator.
• Slack — 1 GB, effectively unrestricted.
• iMessage — around 100 MB before the client offers to downscale it for you.

So before compressing anything: if the recipient is on WhatsApp, send it as a document and the problem disappears. If it has to go through email or Discord, keep reading.

The arithmetic of 10 MB

Video bitrate is measured in megabits per second, and file size is bitrate multiplied by duration. Divide through, and 10 MB works out as roughly 80 megabit-seconds. That gives you a hard budget:

• A 30-second clip can afford about 2.7 Mbps — comfortable, 720p looks clean.
• A 1-minute clip can afford about 1.3 Mbps — 720p is still fine, 1080p starts to show artefacts.
• A 3-minute clip can afford about 0.45 Mbps — which is below what 1080p can survive. You must drop the resolution.
• A 10-minute clip can afford about 0.13 Mbps — unwatchable at any resolution above 360p. Split it, or send it another way.

This is why "just compress it more" fails past a certain length. There is a floor below which the picture simply dissolves into blocks, and the way to stay above it is to give the encoder fewer pixels to describe.

What to change, in order

1. Frame rate to 30 fps. If the clip was shot at 60 fps and nothing moves quickly, this halves the data for no visible cost.
2. Resolution down to 720p, or 480p for a long clip. This is the setting that actually buys you room.
3. Strip the audio if it is going to autoplay muted on a web page. Audio is around 128 kbps of pure overhead in that case.
4. Only then reduce the bitrate, using the budget above as your guide.

Doing it

Open the video compressor, drop the clip in, set the compression level and a resolution cap. For a 10 MB target, choose a 720p cap and the standard level for a clip under a minute; use 480p and the strong level for anything longer.

Two things to expect. First, encoding runs inside your browser at roughly real time, so a three-minute clip takes about three minutes — keep the tab in the foreground. Second, nothing is uploaded, so a file that a server-based compressor would reject on size will process here perfectly well, and private footage stays private.

The output is H.264 MP4 wherever the browser supports it, which is the format that will actually open in email clients, messaging apps and presentation software.

When the target is simply impossible

A ten-minute 1080p recording cannot be reduced to 10 MB and remain watchable. At that point the right answer is not more compression — it is a different delivery route: upload to a cloud drive and send the link, or use a service that accepts documents rather than attachments. No encoder can create information that is not there.