Word error rate (WER)
Word error rate (WER) is the standard accuracy metric for speech recognition: the number of word substitutions, deletions and insertions needed to turn the system's transcript into the correct one, divided by the number of words actually spoken.
A WER of 5% means roughly one error every twenty words. Because WER counts every divergence — including harmless ones like 'okay' vs 'OK' — a system can post a low WER and still read badly, or post a mediocre WER while capturing every fact correctly.
WER is only comparable when measured on the same audio: vendors quoting WER on clean read speech will always beat numbers measured on real meetings, accents and background noise.
Related terms
Frequently asked
What is Word error rate?
Word error rate (WER) is the standard accuracy metric for speech recognition: the number of word substitutions, deletions and insertions needed to turn the system's transcript into the correct one, divided by the number of words actually spoken.
Why does Word error rate matter?
A WER of 5% means roughly one error every twenty words. Because WER counts every divergence — including harmless ones like 'okay' vs 'OK' — a system can post a low WER and still read badly, or post a mediocre WER while capturing every fact correctly.
What terms are related to Word error rate?
Closely related concepts: Character error rate (CER), Automatic speech recognition (ASR), Confidence score — each has its own entry in this glossary.
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