Drop video here or click to upload
Supports MP4, WebM, MOV | Then upload SRT/VTT subtitles
Video is processed entirely in your browser. Nothing is uploaded to any server.
No library loading required. Start processing immediately.
Choose font size, colors, and position to match your needs.
Works with the most common subtitle formats.
Use Video Subtitle when your main goal is accessibility, captioned review copies, or social videos that must play clearly with sound off. If the final subtitled video is too large, continue with Video Compress. If you need the speech extracted separately first, continue with Video to Audio.
No-upload workflow: subtitle files, client drafts, and accessible social videos stay in your browser while captions are burned in.
Yes. Hardcoded subtitles are especially useful for client review links, social clips watched on mute, and any delivery where you can't rely on subtitle track support.
Add subtitles to video online free with FreeToolBox — burn SRT or VTT subtitle files directly into your video as hardcoded captions using FFmpeg.wasm, all in your browser. Hardcoded subtitles are embedded permanently into video frames, ensuring they appear on any device or platform — perfect for social media videos, accessible content, and foreign language videos. Upload your video and subtitle file, choose font style and size, and download the subtitled video.
All processing happens locally in your browser — your video and subtitle files never leave your device. No watermarks are added. Completely free, no account required.
Hardcoded subtitles are permanently burned into the video image — they can't be turned off. Softcoded subtitles are a separate track that players can show or hide. This tool creates hardcoded subtitles, ideal for social media where separate subtitle tracks aren't supported.
SRT (SubRip Text) and VTT (WebVTT) formats are supported. SRT is the most common subtitle format and can be created with any text editor.
Yes. Adjust font size, choose text color, and select subtitle position (bottom or top of frame) before export.
No. FFmpeg.wasm processes everything locally in your browser. Neither your video nor your subtitle file is sent to any external server.
There are two ways to add subtitles, and they behave very differently for the viewer. Hard subtitles are burned into the pixels of the video, so they always show no matter the player, but they cannot be turned off and they permanently alter the footage. Soft subtitles are embedded as a separate track, so the viewer can toggle them, but support depends on the player. Most social platforms and messaging apps display soft subtitle tracks correctly, so for general distribution a soft track is usually the safer, more flexible choice.
Good subtitles are not just about the correct text — they are about timing. Each subtitle should appear roughly when the speaker starts talking and disappear when they stop, long enough to be read comfortably. Text that stays on screen too long makes viewers read ahead and lose the audio; text that flashes too briefly is unreadable. When you add a subtitle track, review the timing against the actual dialogue, not just the text, and adjust any cues that feel rushed or lingering.
Subtitles are often framed as an accessibility feature, but they benefit a much wider audience — people watching with the sound off, in a noisy environment, or in a foreign language. Adding an accurate subtitle track makes your video usable in far more situations and can increase engagement. The main quality bar is accuracy: a transcript with errors is worse than no subtitles because it actively misleads. Proofread the text against the audio before embedding, and remember a subtitle track can be corrected and re-exported without touching the original video.