Many people watch videos on their phones with the sound off: on the bus, at work, or late at night. Without subtitles, they scroll past. Captions also help viewers who are deaf or hard of hearing, people watching in a second language, and anyone in a noisy place. Here's how to add them well.
Burned-in subtitles or a subtitle file?
| Burned-in (open captions) | Subtitle file (SRT or VTT) | |
|---|---|---|
| What it is | Text drawn into the picture | A separate text file with timings |
| Works on | Everywhere: Instagram, TikTok, Facebook, WhatsApp, Reels and Shorts | YouTube, video players, many websites and learning platforms |
| Can viewers turn them off? | No | Yes |
| Can you choose the style? | Yes, any font, colour and position | Mostly decided by the player |
For social media, burn them in. For YouTube or a course platform, upload an SRT file. With the tool below you can do both from the same subtitles.
Step 1: get the words
Typing subtitles by hand takes a long time. The Add Subtitles to Video tool can write them automatically with AI speech recognition (OpenAI's Whisper model), running in your browser, so the video isn't uploaded. It works best with clear speech and little background noise; if your recording is noisy, clean it first with the noise remover.
Always watch the result and fix mistakes, especially names, numbers and technical words.
Step 2: make them readable
- Two lines at most, and about 40 characters per line.
- Give people time to read. A subtitle should usually stay on screen for at least one to one and a half seconds, and longer for longer lines.
- Break at natural points: the end of a sentence or a clause, not in the middle of a name.
- Match the speech: a subtitle should appear when the person starts speaking and disappear soon after they stop.
Step 3: choose a style
- White text with a dark outline or a semi-transparent box is readable on almost any background.
- Use a bold, simple font, large enough to read on a phone.
- For vertical videos, place subtitles slightly above the bottom: apps put their buttons and captions over the lowest part of the screen.
- Big, centred, all-capitals captions are popular on TikTok and Reels, but use them for short phrases only.
What an SRT file looks like
1
00:00:01,000 --> 00:00:03,500
Hello and welcome to the channel.
2
00:00:03,500 --> 00:00:06,200
Today we're making a simple fried rice.Each subtitle has a number, a start and end time (hours:minutes:seconds,milliseconds), and the text. You can open and edit SRT files in any text editor.