How to Add Subtitles to a Video With AI - Free, Auto-Generated (2026)

TL;DR

• Open Magic Hour's Auto Subtitle Generator — no account or download is required, and free users get 3 videos per day.
• Upload your video and AI automatically detects the spoken language and generates timed captions.
• Choose from four visible caption templates: Karaoke, Cinematic, Minimalist, and Highlight.
• Download the video with burned-in captions or export SRT/VTT; the free workflow is limited to 3 videos per day.
• Free workflow generates captions for the first 30 seconds only.

Introduction

As much as 85% of Facebook video views have historically been reported as happening without sound, making on-screen text an important part of social video design. AI subtitle generators solve the tedious part by listening to speech, transcribing it, and timing captions automatically in seconds. This guide shows how to add subtitles to a video with AI using Magic Hour's dedicated Auto Subtitle Generator.

Comparison Table

Magic Hour is the standout if your priority is adding captions without creating an account: its product page offers three free videos per day, while competitors generally require an account for their free workflows.

Why Subtitles Matter More Than Most Creators Realize

• Silent viewing: A widely cited publisher report found that 85% of Facebook video views occurred without sound, which explains why captions became standard for social video.
• Accessibility: Captions let deaf and hard-of-hearing viewers follow spoken content and make videos easier to understand in situations where audio is unavailable.
• Searchability: Caption text gives platforms and search engines additional information about the video's content, potentially improving discovery. Magic Hour specifically positions subtitles as a way to make videos more searchable.

Burned-In Captions vs SRT File: Which Do You Need?

Use burned-in captions when you want the text to appear everywhere the video is played without relying on platform subtitle support. Use SRT or VTT when you want viewers to be able to toggle subtitles or when you need a separate caption asset for another platform or editor. YouTube officially supports both SRT and WebVTT files.

Magic Hour's product page lists SRT/VTT export for YouTube subtitle workflows alongside burned-in captions for social video.

How to Add Subtitles to a Video With AI: Step by Step

Step 1: Go to Magic Hour's Auto Subtitle Generator

Open Magic Hour's Auto Subtitle Generator in your browser. You do not need to create an account, install an app, or enter a credit card, and the free tool provides three videos per day.

Step 2: Upload Your Video

Click Upload video or drag and drop your file into the upload area. The current interface shows a 200MB maximum file size, while the page states that videos with dialogue in 50+ languages are supported and the language is automatically detected.

The free interface currently generates the first 30 seconds, so keep that limitation in mind when testing a longer video.

Step 3: Choose a Caption Style

Before generating, select a caption template. The current interface shows four options: Karaoke, Cinematic, Minimalist, and Highlight.

For TikTok, Reels, and Shorts, a more prominent style such as Karaoke or Highlight can make dialogue easier to follow on a small screen. Cinematic or Minimalist works better when the captions should stay visually secondary.

Step 4: Generate Your Captions

Click Generate and Magic Hour automatically detects the dialogue, transcribes it, and creates timed subtitles. The product page describes the process as taking seconds, although actual processing time depends on the video and current queue.

One important limitation: the current free workflow does not provide word-level transcript editing before export. Magic Hour's FAQ says editing individual words is unavailable in the simplified workflow.

Step 5: Download or Export

Once processing is complete, you can download the captioned video with the subtitles burned into the footage. Magic Hour also advertises SRT/VTT export, which is more useful when you need a separate subtitle track for YouTube or another compatible workflow.

Use the burned-in version for social platforms where you want the captions permanently visible. Choose the subtitle-file export when you want to upload or edit the captions separately.

Tips for the Most Accurate Captions

• Start with clean audio. Background noise, music, and competing sounds can make speech recognition less reliable. Clear, well-recorded speech gives AI a better signal to transcribe.
• Watch for fast speech and accents. AI transcription generally performs best when speakers are clear and well-paced; fast delivery or unusual pronunciation deserves a manual review.
• Review important names and terminology. Product names, technical vocabulary, and proper nouns are common places for transcription errors.
• Check mixed-language videos carefully. Magic Hour says its system can automatically detect languages, including different languages within the same video, but mixed-language clips should still be reviewed before publishing.
• Design for mobile first. Magic Hour handles caption placement and sizing through its style templates rather than giving you separate controls for manually positioning or resizing the text. For vertical videos, Highlight is the safest choice for mobile because its more prominent caption treatment keeps the dialogue easy to read on a small screen. 

What to Try Next

For videos where the person on screen needs to speak new dialogue or a different language, Magic Hour's Lip Sync tool handles the mouth movement while you provide the new audio.
For AI-generated videos you made with other Magic Hour tools, the Auto Subtitle Generator works with the resulting video file just like any other upload. Both tools use the same basic browser workflow: provide your media, let AI process it, preview the result, and export.

Frequently Asked Questions

Is Magic Hour's subtitle generator free?

Yes. The Auto Subtitle Generator provides 3 free videos per day without sign-up, with the free workflow generating captions for the first 30 seconds of each video. Free outputs can be used for personal, non-commercial content, while commercial use requires a paid plan. Paid Creator plans currently start at $12/month when billed annually. 

What languages does it support?

Magic Hour supports 50+ languages and automatically detects the language being spoken. The product page also says it can detect different languages within the same video, making it useful for multilingual content.

Can I edit the captions after they are generated?

Not in the current simplified no-sign-up workflow. If you need to correct individual words, download the SRT file and open it in a free subtitle editor such as Subtitle Edit (desktop) or Rev's online editor, then make your corrections before uploading the subtitle file to your video platform. 

What is the difference between burned-in captions and an SRT file?

Burned-in captions are permanently part of the video, while an SRT file is a separate text-and-timing file that a compatible video platform can display as subtitles. SRT is especially useful for YouTube and workflows where captions need to remain editable.

Will the captions work on TikTok, Instagram Reels, and YouTube?

Yes, burned-in captions are part of the video itself, so they remain visible when you upload the video to social platforms. SRT/VTT files are useful when the destination platform supports separate subtitle uploads; YouTube, for example, officially supports both formats.