Add Captions to a Video on iPhone

Watching with captions versus adding captions

Most of the Apple Support results for this search are about the first kind. Apple's "Display subtitles and captions on iPhone" page (read 30 October 2026) says "iPhone can provide subtitles, closed captions, and transcriptions so you can follow along more easily with audio and video": you go to Settings > Accessibility > Subtitles & Captioning and turn on "Closed Captions + SDH", or tap More Controls and then Subtitles in a video app. Live Captions does something similar for any audio: Apple describes it as "a real-time transcription of spoken audio", switched on under Settings > Accessibility > Live Captions. Both are for you, the viewer; neither writes a word into the video in your Photos library.

Adding captions to your own video means the text has to end up inside the file or on the platform's caption track. On an iPhone that leaves four routes: a browser tool such as CapsAI, typed titles in iMovie, Apple Clips if you already have it, or the captions that Instagram and TikTok generate when you post.

The Safari route in detail

CapsAI runs entirely in Safari, so the phone does the uploading and your browser shows the editor; the speech recognition and the export render happen on CapsAI's servers. That matters on an iPhone for two reasons. First, the phone's storage is not touched until you download the finished MP4. Second, the slowest step is the upload, which is why the steps above say to stay on Wi-Fi and keep the screen awake. A one-minute 1080p clip uploads in seconds on a home connection; a few minutes of 4K can approach the 500 MB free limit, so check the file size in Photos (swipe up on the video) before you start, or use a pack, which takes files up to 10 GB.

The editor is built for a thumb. Each caption is a row you tap; the keyboard opens for the text, and the Start and End fields take seconds as plain numbers, so you never drag a timeline handle on a 6-inch screen. Styles are previewed on your actual frame, with the vertical position adjustable so the text sits above the Reels and TikTok interface. Eight styles are free, including Beast and Poppins Italic; the other 29 come with any paid pack.

The limits: one video per upload, 10 minutes maximum, no SRT or transcript download, and no translation. A 25-minute interview has to be trimmed in Photos first.

iMovie, Clips and the other built-in options

iMovie for iPhone adds titles, not captions. Apple's guide "Add titles" (read 30 October 2026) describes the method: tap a clip in the timeline to reveal the inspector, "Tap the Titles button", "Tap to select a title", then "tap the sample title, tap Edit, then type a new title" and "Tap Done on the keyboard". Every line is typed and placed by hand, and the guide's full contents list, from importing media through themes, audio and sharing, has no captioning, subtitle or transcription topic. Workable for two sentences, not for a minute of speech.

Apple Clips was the one Apple app that wrote text from speech. Its Live Titles were made while recording: the Clips User Guide says "Touch and hold the Record button, and speak while you record" and "Speak faster or slower to control the timing of your title", with the text editable afterwards ("Tap Edit Text, edit the text, then tap Done on the keyboard"). But Apple's "Save your Clips videos" page, published 11 October 2025 and read 30 October 2026, says the app "is no longer being updated, and will no longer be available for download for new users as of October 10, 2025", that it still works "on iOS 26 and iPadOS 26 or earlier", and that earlier downloaders "can still redownload it from your Apple account in the App Store". If you never had it, it is not an option.

Instagram and TikTok caption at posting time. Instagram's help page (read 30 October 2026) says the app "uses speech recognition technology to automatically create captions": while creating a reel or video you open Stickers and "Tap Captions to generate your captions", and for an already shared post you go to Advanced settings and toggle "Enable closed captions". Instagram also warns that captions "may not be available to everyone" and that the default caption language follows your device settings. TikTok offers a comparable auto-caption step in its posting flow with editable text; its help article did not load for us today, so check the current menu in the app. In both cases the captions are the platform's style, on that platform only.

CapCut on iPhone has auto captions inside a full editor. Its own pages disagree on whether that feature is free or part of CapCut Pro, and they could not be read from here today, so this page does not restate a price. The CapCut alternatives page keeps the dated comparison; export a short test from CapCut before you rely on it for a whole video.

iPhone file facts: HEVC, size and where downloads land

Format. Apple's HEIF and HEVC page (published 5 December 2025, read 30 October 2026) says that on iOS 11 or later, "iPhone 7 or iPhone 7 Plus or later" can capture HEVC, that "HEIF and HEVC offer better compression than JPEG and H.264, so they use less storage space", and that you switch under Settings > Camera > Formats, where "Most Compatible" records H.264 and "High Efficiency" returns to HEVC. CapsAI accepts both, so keep High Efficiency for smaller uploads and switch only if another tool refuses HEVC. Our MP4 versus MOV post has the detail on what each container changes.

Size. The free limit is 500 MB per file and 10 minutes per video. Apple's recording guide says only that "Faster frame rates and higher resolutions result in larger video files" without per-minute figures, so treat 500 MB as a few minutes of 4K, longer at 1080p, and check the clip's size in Photos before uploading. A pack raises the limit to 10 GB; the 10-minute cap stays.

Downloads. Safari does not save to Photos by itself. Apple Support (published 17 December 2025, read 30 October 2026) says a downloaded file is "in your Downloads folder in the Files app" and that you can tap "the Downloads button" next to the search field in Safari and then "Tap Downloads to see your downloaded files". Open the MP4 there, tap Share and save it to Photos or hand it to Instagram or TikTok. Do it the same day: free projects are kept for 1 day, paid packs for 3, 7 or 15 days.