You can add captions to a video on an iPhone or Android phone without installing anything: open a browser caption tool such as CapsAI in Safari or Chrome, upload the video from your gallery, correct the words, and download an MP4 with the captions burned in. The built-in options, CapCut's app, Instagram's and TikTok's own captions and Apple's Clips (only if you already have it, since Apple stopped offering it to new users in October 2025), also work, each with a catch. This guide covers the browser route from the gallery, then the built-in options, then a five-point check before you post.
The whole process happens on the phone. There is no desktop step, no cable and no file transfer.
Route 1: a browser tool, straight from the gallery
CapsAI does not have an iOS or Android app. It runs in the phone's browser, which is a feature for a phone-first audience: nothing to install, no app-store region limits, and the same account works on a laptop later. The steps on a phone:
- Open the site in Safari (iPhone) or Chrome (Android) and sign in with Google or an email code. New accounts get 3 free minutes of captioning.
- Tap upload and pick the video from your gallery. CapsAI takes MP4 or MOV up to 10 minutes. iPhone videos are usually HEVC .MOV files; they are accepted as they are, so you do not need to convert to MP4 first. The free limit is 500 MB per file, which covers a few minutes of 1080p phone video; paid packs raise it to 10 GB.
- Pick the spoken language. Eleven are supported: English, Hinglish (Hindi-English mix written in Roman script), Hindi, Bengali, Telugu, Marathi, Tamil, Urdu, Gujarati, Kannada and Punjabi. Captions come out in the language spoken; there is no translation.
- Wait for the draft. A short clip takes a few minutes. Keep the tab open.
- Fix the words in the editor. Tap a caption to retype it, type a new start or end time in seconds to retime it, and pick one of 37 styles. The editor works with touch; a phone screen is small, so zoom in on names and numbers.
- Export and save. The output is one MP4 with captions burned in, 1080p on Starter and up to 4K on Creator and Pro. Save it to the gallery and post from the platform app.
A note on accents: CapsAI's English has been used most on Indian English. If you speak Nigerian, Filipino or Pakistani English, run your own clip through the 3 free minutes and read the draft before you buy a pack. The add captions to video page is the starting point, and the MOV subtitle generator page covers iPhone files specifically.
Phone-specific tips for the browser route
- Upload on Wi-Fi. A 400 MB file over mobile data is slow and may be metered.
- Do not lock the phone during upload. iOS and Android pause background tabs; the upload resumes when you return, but it is faster to leave the screen on.
- Shoot in the final aspect ratio. Captions are placed for the frame you upload. If you will post a 9:16 Reel, record vertical rather than cropping a landscape clip later.
- Low Power Mode slows things down. Turn it off for the few minutes the export runs.
- Project storage is short. Free projects are kept for 1 day, paid packs for 3, 7 or 15 days. Download the export the same day.
Route 2: the built-in options
CapCut's app
CapCut has an auto-captions feature inside its mobile editor. CapCut's site returns HTTP 451 from India, where this guide was written, so we read its pages through a proxy render, and they disagree on price. Its auto caption generator page, read on 18 October 2026, describes the feature as "free of charge" with "multiple languages", while its Standard vs Pro help article, dated 2 April 2026 and read on 19 October 2026, lists auto captions under Pro, and users report a Pro prompt at export. Export a short test clip before you caption a whole video; the CapCut auto captions post has the detail. In practice it is a full editor, so expect more steps than a single-purpose tool, and check whether your spoken language is in its menu before you rely on it.
Instagram's captions on Reels
Instagram can generate captions on Reels and videos from the audio, shown as a caption sticker or a viewer-toggled track depending on the app version and region. Two things to know: the look is Instagram's, with limited styling, and if your video already has burned-in captions you should turn Instagram's off, or viewers see two sets. Instagram's help page on managing reels and video captions could not be read by our tools on 18 October 2026, so check the current steps there or in the app itself. The Instagram Reels caption generator page explains the burned-in alternative.
TikTok's auto captions
TikTok's editor offers auto-generated captions at posting time, with the text editable before you publish, and viewers can toggle captions on finished videos in some regions. TikTok's help article returned an error when we tried to read it on 18 October 2026, so we do not quote it; the menu location moves between app versions. The practical difference is the same as Instagram: TikTok's captions use TikTok's style and exist only on TikTok, while burned-in captions from the TikTok caption generator go with the file to every platform.
iPhone: Clips (existing users only) and iMovie
Apple no longer offers Clips to new users. Apple Support's article Save your Clips videos, published 11 October 2025 and read 19 October 2026, says the app "is no longer being updated" and stopped being available for download for new users on 10 October 2025. If you downloaded Clips before, you can still redownload it from your Apple account in the App Store, and Apple says it keeps working on iOS 26 and earlier. If you have never installed it, you cannot get it now.
For people who still have it, Clips is the Apple app on iPhone that makes captions from speech. Apple calls them Live Titles. The Clips User Guide (read 18 October 2026) describes the method: "Touch and hold the Record button, and speak while you record", and "Speak faster or slower to control the timing of your title." You can add a Live Title to a clip that already has a voiceover; the first time, "you're prompted to allow access to Speech Recognition." The text is editable afterwards: "Tap Edit Text, edit the text, then tap Done on the keyboard." You can also mute your voice and keep the title ("To mute just your voice, tap Mute Recorded Audio"), and record in another language by choosing it in the Live Titles menu and speaking in it.
The catch is the workflow. Live Titles are generated while you record or narrate inside Clips, not from an existing video's dialogue, so they suit a voiceover you perform rather than a conversation you filmed.
Without Clips, no Apple app on the iPhone writes captions from speech. iMovie on iPhone has no auto captions: its titles are text you type yourself (Apple's iMovie for iPhone guide, read 19 October 2026, says to tap the sample title, tap Edit and type), and the guide has no captioning or transcription topic. For a filmed clip with people talking, use the browser route or a platform's auto captions.
Android
Android has no built-in caption generator for exported video. Live Caption on recent Android phones captions audio on the screen for you as a viewer; it does not add text to a file. For a video you will post, use the browser route or an editor app. A subtitle generator for video files that runs in Chrome takes the exported MP4 or MOV from the gallery and returns a copy with the captions burned in.
Which option fits which job
| Option (18 Oct 2026) | Works from an existing video | Styles | Output | Catch |
|---|---|---|---|---|
| Browser tool (CapsAI) | Yes, MP4/MOV up to 10 min | 37 styles, every word editable | MP4 with burned-in captions | No app; 11 spoken languages only |
| CapCut app | Yes | Editor styles | Exported video | Blocked in India; its pages disagree on whether auto captions need Pro |
| Instagram captions | Yes, at posting | Instagram's look | Only on Instagram | Turn off if captions are already burned in |
| TikTok captions | Yes, at posting | TikTok's look | Only on TikTok | Menu moves between versions |
| Apple Clips Live Titles | No; generated as you speak | Clips styles | Video file | Existing users only since 10 Oct 2025; built for narration |
| iMovie (iPhone) | No auto captions | iMovie titles | Video file | Every title typed by hand |
| Android | No built-in option | Use a browser tool or editor app |
What to check before you post
- Read every caption with the sound off. Names, brand names, numbers and code-switched words are what speech recognition gets wrong. Fix them in the editor before export, not in the comments afterwards.
- Check the caption position against the platform UI. On Reels, Shorts and TikTok the bottom and the right edge are covered by buttons and text. Keep captions in the middle band; the Instagram Reels subtitle safe zone tool shows the overlay.
- Two lines, readable speed. If a caption flashes past before you finish it, split it or trim the words. The subtitle reading speed checker flags dense blocks.
- One set of captions. If the video has burned-in text, switch off the platform's auto captions when you post.
- Check the saved file, not the preview. Confirm the resolution and watch the last seconds before uploading.
What to do next
Open add captions to video in Safari or Chrome, upload a clip from the gallery and read the draft. New accounts get 3 free minutes; one-time packs start from $4 (₹49 in India, €4 in the euro area), and watermark-free export comes with every paid pack. Nothing to install, and the same account works on a laptop when you have one.
