How accurate are YouTube automatic captions?

Two kinds of captions

YouTube videos can have captions uploaded or written by the creator, and automatic captions produced by speech recognition. In YouTube’s language menu, automatic tracks are labelled “auto-generated”. A creator track has usually been typed, edited or synced by a person, so it is normally the better source when both exist.

Accuracy depends on the recording

There is no single accuracy figure for automatic captions. The same system can be nearly perfect on a clear studio talk and poor on a noisy street interview. These factors make the biggest difference:

1. Audio quality: background music, wind, echo and cheap microphones cause most errors.
2. Overlapping speakers: when people talk at once, words are dropped or merged.
3. Accents and fast speech, especially in languages with less training data.
4. Rare words: names, brands, jargon and new slang are often replaced by common words that sound similar.
5. Mixed languages: switching languages mid-sentence confuses a single-language model.

Typical mistakes to look for

Automatic captions rarely produce random noise. They produce plausible words that are wrong. Watch for homophones (“their” and “there”), split or joined words, missing negatives such as “can” instead of “can’t”, numbers written differently from how they were said, and names spelled several ways in one transcript. Older automatic tracks may also lack punctuation, which makes long sentences hard to follow.

Proofread in ten minutes

You do not need to check every line of a long video. Focus on the parts you will use.

1. Search the transcript for each name and technical term and fix every spelling at once in Edit mode.
2. Play every passage you plan to quote and correct it against the audio.
3. Scan for numbers, dates and prices, and confirm each against the video.
4. Turn on clean-up mode to hide [Music] tags and filler words before you export.

When the transcript is not enough

Captions only capture speech. Slides, on-screen code, charts and demonstrations are missing from any transcript, and a tutorial can be impossible to follow from the text alone. For those videos, note the timestamps of the visual parts and watch them.

Improving captions on your own videos

If you are the creator, editing your automatic captions in YouTube Studio helps every viewer, including people who rely on captions for accessibility. Our guide to adding captions explains the options.