How to add subtitles to a video

Subtitles make a video understandable on the Tube, in an open-plan office or on a phone on silent. They also make it accessible to people who are deaf or hard of hearing and to anyone who isn’t fluent in the language. Adding them no longer needs editing software: a text file with timings is enough, or a video with them burnt in. What it does need is care: subtitles that are badly split, too fast or out of sync annoy more than they help. In this guide you’ll see which format to choose, which rules professionals follow and how to publish them.

SRT and VTT: the two most common formats

An SRT file is plain text. Each subtitle has a number, an in and out time with milliseconds, and the text on one or two lines. A blank line separates one subtitle from the next. This is what one looks like:

• 1
• 00:00:01,200 --> 00:00:04,000
• Hello everyone and welcome
• to the project presentation.

A VTT (WebVTT) file is almost the same, but it starts with the word WEBVTT, uses a full stop instead of a comma in the milliseconds and supports some formatting and on-screen positioning. It’s the format web players use. If in doubt, keep both: almost every platform accepts at least one of them. Both open in any text editor, so you can fix a typo without special software; just take care not to break the timing lines or the blank lines between subtitles.

Rules for good subtitles

• No more than two lines of 42 characters. More text covers the picture and there isn’t time to read it.
• Between 1 and 7 seconds on screen. Under a second can’t be read; over seven, the eye starts reading again.
• Around 17 characters per second for comfortable reading, and 21 at most. If someone speaks very fast, condense a little.
• Break where the sentence breaks: at a change of speaker, at the end of a sentence, at commas or at pauses.
• Don’t end a line on “the”, “of” or “that”. Those words belong with what follows.

Burnt in or in a separate file

There are two ways to add subtitles to a video, and each has its place. It’s common to use both: the separate file for your website or YouTube, and a burnt-in version of the same video for social media.

• In a separate file (SRT or VTT). Viewers can turn them on or off and pick the language, and the platform fits them to the screen. You can fix them without exporting the video again. Best for YouTube, courses and websites.
• Burnt into the picture. They’re always visible, in any player and on any social network, even ones that don’t accept subtitle files. On the other hand, you can’t remove or fix them without creating the video again. Common in short videos for social media.

Uploading them to YouTube or LinkedIn

Video platforms usually have a subtitles section on the video’s edit screen. On YouTube it’s in the channel studio; on LinkedIn, in the post options when you upload the video. Generally you choose the language, upload the SRT or VTT file and save. Menus change often, so look for the word subtitles or captions. If a network doesn’t let you upload files, use a video with the subtitles burnt in. Once they’re uploaded, watch the whole video at least once: it’s the quickest way to spot a subtitle that comes in late, stays too long or covers something important in the picture, such as a caption or a face.

Generate subtitles for free

Typing subtitles by hand and adjusting every timing takes hours. Our free generator does it for you: upload the video or audio, it transcribes it and gives you an SRT or VTT file following the rules above. It works in your browser, with nothing to install. Check the result before publishing, especially proper names and figures.

With Echo: editor, languages, video and dubbing

If you publish videos often or need several languages, Echo has a full subtitle editor built on the transcript. Subtitles come already split using the rules above, and you fine-tune them as you would in professional software.

• Subtitle editor: fix the text and timings, with undo and redo. It warns you if a subtitle reads too fast.
• Translated tracks: add several languages at once. Each whole sentence is translated and spread across its subtitles, keeping the original timings.
• Download each language as SRT or VTT, or all of them together in a ZIP.
• Video with burnt-in subtitles, in the language you choose, ready to post on social media.
• Synthetic-voice dubbing in Spanish, English, French, Italian or Portuguese, with a different voice for each speaker. Echo doesn’t clone voices.

If your video is a recorded meeting or class, you can also make short clips with animated subtitles for social media, in landscape, square or vertical format. Subtitles and translations are generated on Edorteam’s own servers in the European Union. You’ll find all the details in Subtitles and, if you work with video for the media, in Journalism.