How accurate is AI transcription, really?

This is Talk Type, from the team at Pepys, where we turn talk into text.

How accurate is AI transcription, really? It's the first question everyone asks, and the honest answer is, it depends, mostly on your audio. But we can do better than it depends, because there's an actual way accuracy gets measured, and understanding it tells you how to get more of it.

The measure is called word error rate, and it's exactly what it sounds like. Take the transcript, compare it to a perfect reference, and count the mistakes. There are three kinds. Substitutions, where a word comes out wrong. Deletions, where a word gets dropped. And insertions, where a word appears that nobody said. Add those up, divide by the total number of words, and that's your word error rate. Lower is better. A word error rate of five percent means one word in twenty is off. That sounds small, until it's a name, or a number, or the one line you were going to quote.

Now here's the part that matters. That number is not fixed. The same model, on the same day, will give you a clean transcript of a quiet one on one interview and a rough one of a noisy conference panel. The audio drives almost everything. Clear speech, a close mic, one person at a time, and modern models are genuinely good. Crosstalk, heavy accents, a phone on a table across the room, and accuracy falls off a cliff.

Which means most of your accuracy is decided before you ever hit transcribe. Get the mic close to the person talking. Pick a quiet room. Ask people not to talk over each other. None of that is glamorous, but it moves the number more than any setting in any app.

And when the audio is already imperfect, which it usually is, the smart workflow is not to expect perfection. It's to let the model get you most of the way there in minutes, and then fix the handful of names and terms it got wrong. That's still a fraction of the time it would take to type the whole thing yourself.

So, how accurate is AI transcription? Good enough to trust as a first draft, and great when your audio is clean. The rest is in your hands, at the moment you press record.

That's this episode of Talk Type. The full write up, with the links and sources, is in the show notes. Pepys transcribes any file or link, any length, pay once, and we never train on your audio. Your first sixty minutes are free at pepys dot co. Thanks for listening, and we'll see you next time.