How to compress a video on iPhone (and send one that's too large)

To compress a video on iPhone, you re-encode it at a lower bitrate. Photos and iMovie can trim or export a video, but neither lets you type a file size such as 16, 20 or 25 MB. For that you need an app with a target-size mode: pick the video, enter the size, check the estimate, and compare the result with the original before you keep it.

Apple’s own advice for a video that’s too large is to send it another way — AirDrop, iCloud or Mail Drop — rather than to make it smaller, and the Camera can record smaller files from now on. This guide covers all of these, so you can pick the one that fits. Sending it somewhere specific? See all video compression guides.

Why iPhone videos are so big

A video file’s size is, very nearly, two numbers multiplied together:

size = bitrate × duration

The bitrate is how much data each second of video uses. The iPhone records with plenty of it, so the footage holds up when you edit it — far more than a phone screen can show. Apple’s own guide puts the rest plainly: faster frame rates and higher resolutions result in larger video files.

As of October 2026, depending on the model, the Camera records in HD, 4K and their PAL variants, at 24, 25, 30, 60 or 120 frames per second. A 4K clip at 60 fps carries roughly eight times the pixels per second of 1080p at 30 fps, and its size follows.

The codec matters too. Under Settings → Camera → Formats, High Efficiency records video in HEVC, and Most Compatible records in the older H.264. Apple says HEVC uses less storage at the same visual quality; iPhone 7 and later can record it. When you share an HEVC video with a device that can’t play it, the iPhone may send it as H.264 instead. See H.264 vs HEVC vs AV1 for how much the codec changes.

What the iPhone can do on its own

Before you install anything, check whether one of these already solves your problem:

Trim a video in Photos

1. Open the video in the Photos app and tap the edit button.
2. Drag either end of the frame viewer below the video to the new start and stop, then tap Done.
3. Tap Save Video to replace it with the trimmed version, or Save Video as New Clip to keep both.

A saved trim can be reverted later from the same edit screen. A video saved as a new clip can’t — so if you might want the full length back, save over the original rather than making a new clip.

Send it without compressing

Apple’s guide for long videos points to two routes, as of October 2026:

• AirDrop — the simplest way to a nearby Apple device. In Photos, open the video, tap the Share button, then AirDrop. If the other person isn’t in your contacts, they can set AirDrop to Everyone for 10 Minutes under Settings → General → AirDrop.
• Mail Drop — tap the Share button, then Mail. Mail Drop handles attachments up to 5 GB per message, and the recipient has 30 days to download them. All your Mail Drop attachments together can use up to 1 TB.

Both send the full-size file. That’s ideal for quality, and useless when the problem is a limit at the other end — a chat app’s cap, a 25 MB email attachment, an upload form. That’s when you compress.

Step by step: compress a video on iPhone

These steps use Ninja, which compresses on your iPhone — nothing is uploaded, and there’s no account. Compressing is free, with no watermark; the app is Ninja Video Compress & Convert on the App Store and needs iOS 15.0 or later. The principles apply to any tool.

1. Pick the video. Open Ninja and choose from your Photos library. You can also share a video into Ninja from the Share button in Photos or another app. iOS hands Ninja a copy that way, so the original always stays where it is.
2. Choose how small. Leave it on Ninja Auto for most videos: it reads the video’s bitrate, resolution and codec and picks the biggest saving that still looks sharp. If you have a hard limit, choose Target size and type the number, or pick a share preset — WhatsApp, Gmail, iMessage / MMS and twelve others.
3. Read the estimate. Ninja shows the expected size and percentage saved before anything is encoded. If it isn’t small enough, try Quality → Small or a lower resolution.
4. Compress, and keep Ninja open. The iPhone’s hardware encoder does the work, so a 4K clip takes minutes. iOS limits how long an app can keep working in the background, so for a long batch, stay in Ninja. If iOS does pause it, the unfinished videos stay in the queue.
5. Inspect the result. The Reveal shows the original and the compressed copy at the same moment. Drag the divider and pinch in on detail — hair, leaves, text.
6. Decide what happens to the original. Keep both, move the original to the in-app Ninja Vault, move it to Recently Deleted (restorable for 30 days), or Replace original — the compressed video takes its place, keeping its date and location so your library’s timeline doesn’t break. Ninja only offers the last three after the new file passes nine checks: it opens, its length matches, its audio survived, frames decode at the start, middle and end, it saved to your Photos library and reads back, and it’s genuinely smaller.

How to compress an iPhone video to a specific size

Multiply the size you need in megabytes by 8 and divide by the video’s length in seconds: that’s the bitrate that fits, in megabits per second. A 2-minute clip that must stay under 25 MB has about 1.6 Mbps to spend in total (25 MB × 8 ÷ 120 seconds, less a small allowance for the file’s own overhead). Take away 128 kbps for the sound and about 1.5 Mbps is left for the picture — enough for 720p at 30 fps, not for 1080p. In Ninja, choose Target size, type 25 and the app works this out for you; for any other limit, calculate the exact bitrate for a target size before you pick a setting.

Which setting for which job

Tips that make a real difference

• Compress from the original, once. Re-compressing a video that’s already been compressed stacks the losses. If you need a WhatsApp copy and an archive copy, make both from the original.
• Drop 60 fps to 30 for talking, keep 60 for motion. Halving the frame rate frees bitrate for sharper frames — good for a speech, bad for a match.
• Lower the bitrate before the resolution. Downscale only when the bitrate gets too thin to fill the picture; that’s when edges start to smear.
• Fix it at the source. If most of your videos end up on a phone screen, recording 1080p instead of 4K under Settings → Camera → Record Video saves space on every clip you take from now on.

Frequently asked questions

Can I compress a video on iPhone without an app?

Not in the sense of choosing a smaller file size. Photos can trim a video, the Share button’s Options can change its format, and the Camera can record smaller files in future. But a format change isn’t a saving: Most Compatible may convert the file to a more widely playable format, and Apple describes HEVC — the format it converts away from — as the one that uses less storage. To make an existing video meaningfully smaller, re-encode it.

What’s the best app to compress a video on iPhone?

We make Ninja, so we won’t rank apps. Whichever you try, check five things: it compresses on the phone instead of uploading your video; it can hit a size you type, not just “low, medium, high”; it lets you compare the result with the original before you keep it; free exports carry no watermark; and its App Store privacy label says what it collects. Ninja does all five, and its App Store label reads Data Not Collected.

Does compressing reduce quality?

Technically yes — every lossy re-encode discards some data. In practice, iPhone videos carry so much extra data that a well-chosen setting removes much of the file before the difference shows on a phone. Compare the two at the same moment, zoomed in, and judge for yourself.

Is my video uploaded anywhere?

Not with Ninja. It compresses entirely on the device. On iPhone, the app’s code contains no network address and no HTTP client — there’s no server to send your video to. Buying Ninja Pro goes through the App Store; Ninja never sees your payment details.

Is it free?

Compressing is free, forever: every size mode and share preset, with no watermark and no daily cap. Ninja Pro is optional — it adds batches of more than three videos, eight advanced tools and HEVC, VP9 and AV1 output, for $2.99 a month, $14.99 a year or $29.99 once (US prices; the App Store sets local prices).

Why did Ninja keep my original?

Either because you chose Keep both, or because the video came in through the Share button. iOS passes a shared video to Ninja as a copy and doesn’t say which Photos item it came from, so Ninja won’t pretend it can remove the original — it tells you it kept it.

Sources

Every limit above was checked against these on 18 October 2026. Platforms change them; if one has moved, tell us.

1. iPhone User Guide — Record a video (video recording formats)
2. Apple Support — Using HEIF or HEVC media on Apple devices
3. iPhone User Guide — Trim video length, adjust speed, and edit audio
4. iPhone User Guide — Share long videos
5. iPhone User Guide — Share photos and videos
6. Apple Support — Mail Drop limits
7. Gmail Help — Attach files