How to add captions to a video in your browser

Open a browser caption tool, drop in the clip, check the transcript, pick a style and export. For a short clip that takes a few minutes, and you do not need a desktop editor or to upload the whole video to someone's server.

Here are the steps, plus what to check before you post.

What you need

A video clip and a browser.

You do not install software, create a project or learn a timeline editor first. The clip can be vertical for TikTok, Reels and Shorts, or wide for YouTube. The export keeps the original size.

The steps

1. Open the caption generator and drop in your clip.
2. It transcribes the speech with a timestamp on every word.
3. Read the captions and fix any word the model misheard.
4. Pick a style: font, color, outline and how the active word is highlighted. A preset gets you most of the way.
5. Export a burned-in MP4, or download an .srt or .vtt subtitle file.

Choosing a look usually takes longer than the rest.

Check the words before you publish

Speech recognition gets most words right but not all of them. Brand names, slang and two people talking at once are where it slips.

In the studio every caption sits on a timeline over the audio waveform, so you can see where each line falls. Select a caption to fix its words, drag it to change the timing, or split and merge captions until the pacing feels right.

Keep your footage private

When you upload a video to a web app, a copy of it lands on a server you do not control. For a throwaway clip that may be fine. For client work, unreleased footage or anything personal, it is worth avoiding.

ReelCaption processes the video in your browser, so it never leaves your device. Only the audio track is sent for transcription, and ReelCaption does not store it.

Burned-in captions or a subtitle file?

Burned-in captions are part of the picture, so they show whether or not the viewer has subtitles on. A subtitle file stays separate, which suits long videos and viewers who want to control how captions look. More in SRT vs burned-in captions.

Make them readable

Captions have to be read at a glance on a small screen with the sound off. Keep each line short, time the highlight to the spoken word, and give the text enough contrast for your busiest shot. The full rules are in how to style captions people actually read.

Check where each platform puts its buttons

Each app draws its own buttons and labels over your video, so a caption position that works on YouTube can end up under the TikTok icons. The platform guides cover safe zones and sizes for TikTok, Instagram Reels, YouTube Shorts and YouTube.

Try it

Drop a video into the free caption generator. The first 2 clips of up to 60 seconds need no account.