AssemblyAI vs OpenAI
AssemblyAI Universal-3 Pro vs OpenAI gpt-transcribe for transcription. Price: $3.5 per 1000 min vs $4.5 per 1000 min — edge AssemblyAI WER: 3.1% vs 3.3% — edge AssemblyAI Computed from public benchmarks with dated sources; updated 2026-08-20.
Head to head
| Axis | AssemblyAI Universal-3 Pro | OpenAI gpt-transcribe | Edge |
|---|---|---|---|
| Price | $3.5 per 1000 min | $4.5 per 1000 min | AssemblyAI |
| WER | 3.1% | 3.3% | AssemblyAI |
| Langs | 99 | — | — |
| Latency | 150 ms | — | — |
| diarization | ✓ | — | — |
| timestamps | ✓ | — | — |
| vocab | ✓ | ✓ | — |
Strengths & caveats
AssemblyAICheapest of the directly-comparable dedicated APIs ($3.50/1000 min) with the widest language coverage (99) and full diarization, timestamps and custom vocabulary; ~150 ms P50 streaming. Accuracy (3.1% WER) trails the leaders; the cheaper legacy Universal-2 tier is less accurate still. AssemblyAI now lists Universal-3.5 Pro as its flagship at the same $3.50/1000 min, but no independent leaderboard score exists for it yet, so the WER here still refers to Universal-3 Pro.OpenAIOpenAI's current recommended transcription model: both cheaper ($4.50/1000 min) and more accurate (3.3% WER) than the gpt-4o-transcribe tier it supersedes, with a keywords parameter for biasing terms. Returns plain JSON: no word-level timestamps (only the legacy whisper-1 emits them) and no native diarization — OpenAI ships a separate gpt-4o-transcribe-diarize model for speaker labels. Also billed per token as an alternative to the per-minute rate.
Sources
- Artificial Analysis — Speech to Text2026-08-20
- Open ASR Leaderboard2026-06-19