FileDial › Guides › Video and subtitles
How to compress a video for email on a Mac
By Himanshu Ranjan · Updated 8 November 2026
To email a video from a Mac, get it under the provider's attachment limit. Gmail allows 25 MB on personal accounts. Select the file in Finder and run FileDial's Compress › Compress under 25 MB. It saves a new copy beside the original, offline, so nothing is uploaded and you keep your full-quality file.
Why your video will not attach
Email was designed for text, so providers cap how much you can attach. Gmail lists 25 MB as the attachment limit for personal accounts, and work or school accounts follow limits set by the Google Workspace administrator. If the total goes over, Gmail removes the attachment and puts a Google Drive link in the message instead. That works, but the recipient then needs access to Drive and you have handed the file to a cloud service.
Attachments also grow when sent. Email systems encode attachments as text, which makes the message bigger than the file you picked, so aim comfortably under the limit rather than exactly at it. A 24 MB clip is a risky choice for a 25 MB limit.
Compress under 25 MB with FileDial
The fastest route is the tool named for the job. It takes a video of any size and produces a new copy aimed at the 25 MB ceiling. Your original is untouched, and the result card shows the size before and after so you can see what you saved.
- In Finder, select the video.
- Hold the right Option key to open the dial, or right-click and choose Open in FileDial.
- Open Compress, then choose Compress under 25 MB.
- Wait for the result card, then attach the new file from the same folder to your email.
When 25 MB is too tight
Squeezing a long video under 25 MB costs quality, because the tool has to spend fewer bits on every second. If the clip is more than a minute or two, the picture will look softer. You have three honest options: trim the video first so there is less to compress, drop to a lower resolution, or send a link instead.
FileDial's Cut › Trim… removes the parts nobody needs to see before you compress. If the recipient uses a different provider, check their limit too, because the smaller of the two limits wins. For larger files, Compress › Compress to size… lets you pick your own target, and Compress under 50 MB suits services that accept more.
Built-in macOS alternatives
QuickTime Player can shrink a video without extra software. Open the movie, choose File > Export As, and pick a lower resolution such as 720p or 480p. At 4K or 1080p you can pick Smaller File Size (HEVC) or Greater Compatibility (H.264). Apple notes that exported video is a .mov file. You cannot tell QuickTime a target size, so you may export more than once.
Mail Drop in the Mail app also sends large attachments through iCloud, but that does involve an upload to Apple's servers. Compressing locally keeps the file on your Mac until you choose to send it.
A realistic plan for a long video
Suppose you have a ten-minute recording and a 25 MB limit. The maths in Wikipedia's bit rate article shows why that is hard: file size is roughly bit rate times duration divided by eight, so 25 MB spread over 600 seconds leaves a very low bit rate, and the picture will show it. The honest answer for long videos is not heavier compression but a different delivery method.
Send a short highlight by email and put the full version somewhere the recipient can download it. Or split the video into parts with Cut › Split into parts under N MB…, which makes parts without re-encoding, so each part keeps full quality. The recipient then has several attachments to open in order, which is clumsy but lossless.
Check before you send
Play the compressed file once through before attaching it, looking at faces, any small text and the audio. If the result looks too rough, go back to your original and try a different combination, for example trimming first or choosing a size target slightly above the limit and checking whether the file really lands under it. FileDial's result card shows the size, so you do not have to guess.
Also check the file name and the folder: the new copy sits beside the original with its own name, so make sure you attach the small one and not the master.
Keep a private clip private
A video of a family event, a screen recording with customer data, or a work walkthrough is often exactly what you are emailing. Online compressors need you to upload it first. FileDial runs every tool on your Mac and works with Wi-Fi off, so the only copy that leaves is the small one you attach. The privacy and why-offline guides explain the risks of upload-based converters in more detail.
Questions
What is the Gmail attachment limit?
Gmail's help page says personal accounts can attach up to 25 MB, and work or school accounts follow the limit their Google Workspace administrator sets. Above the limit, Gmail replaces the attachment with a Google Drive link in the email. Recipients with a stricter mailbox limit than yours are the usual cause of bounced mail, so leave some margin.
Will compressing ruin the quality?
It lowers quality somewhat, because the file must carry less data. For a short clip the difference is usually small on a phone or laptop screen. For a long video aimed at a tight limit, expect a softer picture. Trimming first helps, and your original stays unchanged. Sound is rarely the problem. Check faces and any small text on screen after compressing, since those show the loss first.
Does FileDial upload my video to compress it?
No. All 525 tools run on your Mac, and files are never uploaded. Every tool works with Wi-Fi off. The result is saved as a new file beside the original, and you can undo it. The only things that go online are the licence check and optional anonymous usage counts, which never include file names or contents.
What if the video is still too big?
Trim it, choose a lower resolution such as Compress › Compress to 720p, or share a link through a service you trust. Splitting is another option: Cut › Split into parts under N MB… makes parts without re-encoding, though the recipient must play them one after another. Often a short highlight by email plus a link to the full version works better than one heavily squeezed file.