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On device · about a minute

How to add subtitles to a video on iPhone

Most ways to subtitle a video on iPhone mean either typing every line by hand in iMovie or uploading your clip to a website. Just Captions transcribes the speech automatically, on your device, and lays down clean subtitles in about a minute.

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The short version: open Just Captions, drop in your clip, and it transcribes the speech on your iPhone and times subtitles to every word. Pick one of 15 caption styles, then export an MP4 with the captions burned in. No line-by-line typing like iMovie, and on-device transcription available.

Step by step

Add subtitles in four taps

  1. Add your clipOpen Just Captions and drop in the video, or pick up to 20 from your camera roll. Portrait, square and landscape are all handled.
  2. Let it transcribeThe app listens, transcribes the speech on your device, and times clean subtitles to every word. It understands 50+ languages and captions in whatever is spoken.
  3. Pick a styleChoose from 15 caption styles — White box, Yellow box, Gray box or Yellow outline — already sized for one-glance reading.
  4. Export the videoTap any line to fix a name or term, then export an MP4 with the subtitles burned in, ready to post or send anywhere.
Need another language? AI Auto Translate turns finished subtitles into another language while keeping the same timing, so you can export a second cut for a different audience.
Your options

Ways to subtitle an iPhone video, compared

There are four common routes. Only one is automatic, private, and produces captions that stay visible when the clip autoplays.

MethodWhat it's actually like
iMovieFree, but you type and time every subtitle line by hand — slow for anything past a few sentences, and there's no auto-transcribe.
Settings → Accessibility → CaptionsOnly displays an existing closed-caption file during playback. It can't create subtitles for your own video.
Upload-based subtitle websitesOften auto-transcribe, but you upload your video to their servers first and work in a browser timeline.
Just CaptionsAuto-transcribes on your device, burns captions into the MP4, and keeps processing local in on-device mode. About a minute per clip.

Just Captions is the automatic, on-device option — no manual typing and no upload.

FAQ

iPhone subtitles, answered

How do I add subtitles to a video on iPhone for free?
Open Just Captions, drop in the clip, and it auto-transcribes and times the subtitles for you on device. You can caption up to three videos a day free, with a watermark and no account.
Can iMovie add subtitles automatically?
No. iMovie only lets you add and position text manually, line by line — it has no speech-to-text. For automatic subtitles you need a tool that transcribes the audio, like Just Captions.
Do I have to upload my video?
No. Just Captions transcribes and renders on your iPhone, so on-device recognition can keep processing local. Many web subtitle tools upload the file to a server first.
Should social captions be burned in?
For TikTok, Reels and Shorts, yes — burned-in (open) captions stay visible when a clip autoplays on mute, which is when most viewers decide whether to keep watching.
Keep going

Captions for every feed

Captions for TikTokSafe zones and styling tuned for TikTok.Read →
Captions for Instagram ReelsStyling tuned for the Reels player.Read →
Free online subtitle toolCaption a clip in your browser, no install.Try it →

Subtitle your next video. Automatically.

Three videos a day free, no card, on-device transcription available. Drop in a clip and watch the captions write themselves.

Download on theApp Store

Just Captions 2.6: three videos a day free, with a watermark. Choose from 15 styles: seven static styles are free; animated styles require Pro, with one free single-video Emoji export. Pro removes the watermark. On-device transcription is available after the model download. Optional cloud recognition sends audio for processing; AI editing and translation send caption text. These online features need a connection.