AssemblyAI Universal 3.5 Pro vs GPT-4o Transcribe
Accuracy and speed
Left gets fewer words wrong. Lower has the final text ready sooner.
- Universal 3.5 Pro1.93% · 180ms
- 4o Transcribe3.90% · 652ms
AssemblyAI Universal 3.5 Pro is ahead of GPT-4o Transcribe on both datasets together, the Pipecat Dataset, the Ocular Dataset and final-text delay. AssemblyAI Universal 3.5 Pro has a newer release: AssemblyAI Universal 3.6 Pro vs GPT-4o Transcribe.
Last updated Methodology by Dileep Chagam
Who is better at what
- Overall WER2.72%6.85%
- Pipecat Dataset WER1.93%3.90%
- Ocular Dataset WER4.23%12.45%
- Time to first text489msn/a
- Final-text delay180ms652ms
Lower is better on every measure. Too close to call means the likely ranges overlap.
Universal 3.5 Pro vs 4o Transcribe FAQ
Which is more accurate, AssemblyAI Universal 3.5 Pro or GPT-4o Transcribe?
AssemblyAI Universal 3.5 Pro is more accurate on both datasets. On the 1,000 public Pipecat clips, AssemblyAI Universal 3.5 Pro scores 2.72% and GPT-4o Transcribe 6.85%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 4.13 points. On the eight licensed Ocular recordings, AssemblyAI Universal 3.5 Pro scores 1.93% and GPT-4o Transcribe 3.90%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 1.97 points. Word error rate counts incorrect, missing, and extra words, so lower is better.
AssemblyAI Universal 3.5 Pro is more accurate on both datasets. On the 1,000 public Pipecat clips, AssemblyAI Universal 3.5 Pro scores 2.72% and GPT-4o Transcribe 6.85%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 4.13 points. On the eight licensed Ocular recordings, AssemblyAI Universal 3.5 Pro scores 1.93% and GPT-4o Transcribe 3.90%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 1.97 points. Word error rate counts incorrect, missing, and extra words, so lower is better.
Final-text delay was not measured for one or both, so speed cannot be compared. Both are measured on the same 206 streamed turns.
AssemblyAI Universal 3.5 Pro makes fewer errors on real conversations, and the two are not separated on speed. A voice agent cannot reply until the final transcript arrives, and the Ocular recordings are real conversations.
Only AssemblyAI Universal 3.5 Pro. GPT-4o Transcribe returns no text until the speaker stops, which matters if your agent reacts to partial transcripts.
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