How to Compress a Video on iPhone (4 Ways, Compared)
Why iPhone videos get so big
A three-minute clip off an iPhone can easily land somewhere north of a gigabyte, and nothing about it looks unusual in Photos. The size comes from what the camera records by default, and most people never change those defaults because there's no reason to until something won't send.
Four settings do most of the damage. 4K resolution is the default on every recent iPhone, and 4K at 60fps runs roughly six times the data rate of 1080p at 30fps. HEVC (H.265) is more efficient than the older H.264, which sounds like it should help — and it does, per pixel — but it also let Apple raise the default resolution and frame rate, so files got bigger anyway. Cinematic mode records depth information alongside the picture so the focus can be changed later, which is genuinely useful and genuinely expensive in megabytes. And slow-motion captures at 120 or 240 frames per second, meaning four to eight times as many frames as normal video for the same wall-clock length.
ProRes, on Pro models, is in its own category — it's a near-lossless editing format, not a delivery format, and it runs on the order of several gigabytes per minute at 4K. If you turned it on for a shoot and forgot to turn it off, that's almost certainly your answer.
None of this is a fault. It's the camera doing what it was configured to do. It only becomes a problem at the moment you try to email, upload or message the result.
Option 1: Mail's attachment size options
The fastest route, if you're emailing the video anyway. Attach the video to a message in the Mail app, tap Send, and iOS offers a size menu before it actually sends: Small, Medium, Large and Actual Size. Pick anything but Actual Size and Mail re-encodes the video down before it leaves the phone.
What's good: zero setup, nothing to install, and it's built into the flow you were already in.
The catch: those four options are all you get. There's no way to see the resulting file size before you commit, no way to target a specific number like 25MB, and the whole thing only exists inside Mail. You can't use it to shrink a video for Discord, for a web form, or just to free up storage. "Medium" on a short clip and "Medium" on a ten-minute recording produce wildly different results, and you find out which one you got after sending.
Use it when you're emailing one clip and don't care about the exact size. Skip it for anything else.
Option 2: The Shortcuts app
iOS ships with a Shortcuts action called Encode Media that can re-encode a video at a chosen resolution, and it's the most flexible option that's already on the phone. Build a shortcut that takes a video as input, runs Encode Media with a resolution cap and a quality preset, and saves the result — then run it from the Share sheet on any video in Photos.
What's good: it's free, it's built in, it works on any video rather than inside one app, and once the shortcut exists you can reuse it forever. If you compress video on your phone regularly, this is worth the twenty minutes.
The catch: you have to build it, or find and trust someone else's. Encode Media targets a resolution and a quality preset, not a file size — so hitting "under 25MB" is still trial and error, just with more knobs. And shortcuts have a habit of breaking quietly across iOS updates.
Use it if you compress video weekly and like the idea of a reusable button. Skip it if this is a one-off and you'd rather not spend the setup time.
Option 3: App Store compressor apps
Search "video compressor" in the App Store and you'll get dozens of results, most of them free to download. The good ones give you real control — resolution, bitrate, sometimes a target file size — and they handle batches properly.
What's good: proper compression controls, offline, and batch processing that the built-in options don't offer.
The catch: you're installing software to solve a one-file problem, and the free tiers vary enormously. Some add a watermark. Some cap the length or resolution until you subscribe. Some want access to your entire photo library when they only need one video. A few upload your footage to their own servers to do the work, which most people assume an "app" wouldn't do. Read what the free tier actually includes before you commit a video to it.
Use it if you compress video constantly and find one you trust. Skip it for a single clip.
Option 4: Compress it in Safari, no app
Modern iPhone browsers can encode video natively, which means a web page can now do the compression on the phone itself rather than uploading anything. SquishyFile is built on exactly that: open the page in Safari, tap to pick a video from Photos, set either a compression level or an exact target size in MB, and save the result back to Photos or Files.
What's good: nothing to install, no account, no watermark, and — the part the other three options can't do — you can type an exact number. If the limit you're fighting is 25MB for email or 16MB for WhatsApp, you type 25 or 16 instead of guessing at a quality preset and checking afterward. The video never leaves the phone, because the encoding runs in the browser rather than on a server.
The catch: it runs on your phone's hardware, so a multi-gigabyte 4K file takes real time and real battery, and you need to keep the tab in the foreground while it works — Safari throttles background tabs aggressively, which is the usual reason a job appears to stall. An older iPhone on a very large file is slower than a desktop app would be.
Which one to actually use
| Situation | Use |
|---|---|
| Emailing one clip, exact size doesn't matter | Mail's size options |
| Need it under a specific number of MB | Safari (target size field) |
| Compressing videos most weeks | A Shortcut, or a trusted App Store app |
| A folder of clips, all to the same size | App Store app with batch, or Safari one at a time |
| Don't want to install anything | Safari, or Mail if you're emailing it |
Stop the problem at the source
If you keep running into this, change what the camera records. In Settings → Camera → Record Video, dropping from 4K 60fps to 4K 30fps roughly halves the data rate, and 1080p 30fps is a fraction of either — still more than enough resolution for anything that ends up on a phone screen, a social feed or a video call.
Also in Settings → Camera, Formats lets you choose between "High Efficiency" (HEVC) and "Most Compatible" (H.264). High Efficiency produces smaller files; Most Compatible produces larger ones that open without fuss on older Windows machines and some upload forms. If your problem is size, stay on High Efficiency and compress when you need to share — switching to Most Compatible makes files bigger, not smaller.
And check whether ProRes is on if you have a Pro model. It's the single biggest multiplier in the list, and it's easy to leave enabled by accident.
Common questions
How do I compress an iPhone video without losing quality?
You can't re-encode with zero loss, but you can make it invisible in practice. Compress from the original rather than an already-compressed copy, use a light setting, and if you're targeting a size, give a longer video a more generous number — the same 25MB stretches much thinner across ten minutes than across ten seconds.
How do I compress an iPhone video for email?
Target 25MB. That clears Gmail, Outlook and most corporate inboxes. Mail's own "Medium" option often lands near it by accident; typing 25 into a target size field gets you there on purpose.
Does compressing a video delete the date or location?
It shouldn't. Compression rewrites the video and audio streams, not the metadata Photos uses to sort your library — though some third-party apps do strip it, so check if that matters to you.
Why is my iPhone video still huge after compressing?
Usually one of three things: you compressed an already-compressed copy instead of the original, the clip is long enough that even a heavy setting leaves it large, or it's ProRes, where the starting size is so far above normal that a single pass barely dents it.
Can I compress a video on iPhone without an app?
Yes — Mail's attachment sizes and the Shortcuts app are both built in, and a browser-based compressor runs in Safari with nothing to install. Only the last of those lets you name an exact file size.
The short version
Four routes, and they sort cleanly. Mail's size options are the fastest when you're already emailing. Shortcuts is the best free reusable option if you'll do this often. App Store apps are worth it only if you compress constantly and find one whose free tier is honest. And if you need a specific number of megabytes — which is usually the real requirement hiding behind "make it smaller" — compressing it in Safari is the only one of the four that lets you just type the number.