This tool lets you add captions to a video from an SRT or VTT subtitle file you already have. It draws each line of the file onto the picture at the right moment. It does not listen to the speech and write captions for you, so you need the file before you start.
Captions help people follow a video with the sound off, in a noisy place, or in a language that is not their own. A separate subtitle file only helps if the player loads it, and many sites and apps do not. When you burn subtitles into the video, the words become part of the picture and show everywhere. It all happens in your browser, so neither your video nor your subtitle file is uploaded.
This guide covers what you need, how to set the look, and what to expect from the result, including the one thing you cannot undo.
How to add captions to a video
- Drop your video onto the page. You can add more files if they share one subtitle file.
- In the Subtitle file slot, add your SRT or VTT file. The Lines list shows the subtitles the tool found, and a click on a line jumps the preview to it.
- Set the Size, the Text colour, the Outline colour and the Distance from the bottom.
- Check the preview. Move through the clip and watch the lines appear and leave on cue.
- Press Burn in subtitles. Save the result, or download several results as a zip.
You need an SRT or VTT file for this. The tool does not write captions from what people say in the clip. Until a file with at least one line is loaded, the Burn in subtitles button stays greyed out and the line under it reads "Add a subtitle file first". If the file cannot be read, the slot says why, so you can fix the problem and try again.
The preview helps you catch problems early. The current line is drawn on the stage as you play, and the cues also appear on the timeline. If a line comes too early or too late, fix the times in your subtitle file with a text editor, then add the file again. The tool burns in the timing exactly as the file gives it.
SRT and VTT subtitle files explained
A subtitle file is a plain text list of lines, each with a start time, an end time and the words to show. This tool reads two formats: SRT and VTT. Other subtitle formats are not accepted.
| Format | File ending | What to know |
|---|---|---|
| SRT | .srt | The most common format. Numbered lines with start and end times. |
| VTT | .vtt | Used on the web. Starts with a WEBVTT header line. |
Whether you add an SRT to a video saved as MP4, MOV, MKV or WebM, the result is always a new MP4 file with the lines drawn into the picture.
Styling inside the file is ignored
Some subtitle files carry colours, fonts or positions. This tool does not use them. The settings on the page are used instead, so every line in the video gets the same look. If your file asks for red italic text at the top, you will still get the colour, size and margin you choose here.
What happens to messy lines
Empty lines are dropped. Lines that overlap are trimmed, so one line ends where the next begins. Curly braces and backslashes are cleaned out of the words. The Lines list and the timeline show the result of that clean-up, so what you see is what gets burned in.
Set the size, colour and margin of burned-in subtitles
Four controls shape how subtitles look. Subtitles always sit at the bottom centre of the picture and always have an outline, because that is the layout that reads best over moving video.
- Size runs from 3% to 9% of the video height, in steps of half a percent. Small sizes suit film-style subtitles. Larger sizes suit short clips watched on a phone.
- Text colour has four swatches: white, ink, yellow and red. White and yellow are the usual choices.
- Outline colour can be black, white, yellow or red. A black outline on white text works on almost any scene.
- Distance from the bottom runs from 2% to 20% of the video height. Raise it if the lines collide with a logo or the controls of a player.
Changing a setting updates the preview at once, so you can test a combination in seconds. If the lines sit too close to the edge, raise the distance from the bottom. If the text feels heavy, lower the size by half a percent at a time. The tool keeps the lines inside the frame, with a margin at each side. Long lines wrap onto a second line instead of running off the edge.
Hardcoded subtitles or a separate file: which to use
Burned-in subtitles are also called hardcoded subtitles. To hardcode subtitles is to embed the words in the picture itself: they are drawn into every frame, so they cannot be switched off or changed later. A separate file is not part of the picture. It stays editable, but it needs a player that supports it.
| Burned in | Separate file | |
|---|---|---|
| Shows on every player and platform | Yes | Only where the player loads it |
| Can be turned off by the viewer | No | Usually yes |
| Can be edited afterwards | No, you start again from the original | Yes |
| Style comes from | The settings on this page | The player |
Burned-in subtitles are part of the picture, and you cannot turn them off later. Keep your original video if you want a version without them. This tool always writes a new file and leaves your original untouched.
Think about who will watch. A clip for a phone screen needs larger letters than a film shown on a monitor, because the whole frame is small. A clip with a lot of dialogue needs a smaller size so that two lines fit without covering the action. Try a few sizes in the preview before you commit. Social clips, messaging apps and screens in public places are the usual reasons to burn subtitles into a video. If you only want a few words on screen, such as a name, use add text to video instead, and for a heading across the top of the opening frames, use the video title maker.
Add subtitles to video privately, for free
Your video and your subtitle file are read and drawn on your own device. Nothing is uploaded, and the server does no video work. The tool is free, with no account and no watermark. Video tools are not counted in the free daily limit, which applies to document conversions only. See the privacy page for details.
Most videos have no size limit. Some files, such as certain AVI or WMV videos, are handled at a slower pace, and those can be up to 2 GB. The subtitles use Inter Bold. The tool works in current Chrome, Edge and Firefox, and the result is an MP4 file.
Before you burn, you may want to trim the video so the subtitle times still match the clip. After you burn, you can compress the video to make it easier to share.
Burn your subtitles in now
To add captions to a video, add the clip, add your SRT or VTT file, choose the size, colours and distance from the bottom, and press Burn in subtitles. The words become part of the picture and show on every player.
Use the tool above to add subtitles to a video with your own files. Remember to keep your original video, since burned-in subtitles cannot be removed. For a logo on the same clip, try watermark video.
