AssemblyAI vs OpenAI Whisper
An independent, side-by-side comparison to help you pick the right tool. Pricing, features, strengths, and trade-offs.
Free tier (up to 185 hrs pre-recorded) / Pay-as-you-go from $0.15/hr (Universal-2) or $0.21/hr (Universal-3.5 Pro) / Streaming from $0.15/hr
Free (open source) / API $0.006/min (whisper-1, removed from the API Feb 26, 2027)
At a glance
| AssemblyAI | OpenAI Whisper | |
|---|---|---|
| Pricing | Free tier (up to 185 hrs pre-recorded) / Pay-as-you-go from $0.15/hr (Universal-2) or $0.21/hr (Universal-3.5 Pro) / Streaming from $0.15/hr | Free (open source) / API $0.006/min (whisper-1, removed from the API Feb 26, 2027) |
| Type | Transcription | Transcription |
Feature comparison
| Feature | AssemblyAI | OpenAI Whisper |
|---|---|---|
| Speech-to-text API (pre-recorded and real-time streaming) | No | |
| LLM Gateway (formerly LeMUR) | No | |
| PII redaction | No | |
| Topic and sentiment detection | No | |
| Speaker diarization | No | |
| 99 languages on Universal-2 | No | |
| 100 language support (including Cantonese) | No | |
| Local processing option | No | |
| Open-source model (MIT) | No | |
| OpenAI API access (whisper-1 deprecated; removal from the API on Feb 26, 2027) | No | |
| Speaker diarization (via community tools) | No |
What makes each tool different
AssemblyAI
AssemblyAI goes beyond transcription to provide audio intelligence: topic detection, sentiment analysis, entity recognition, PII redaction, and auto chapters. Its LLM Gateway (formerly LeMUR) lets you apply language models to transcribed audio through the same API.
OpenAI Whisper
Whisper changed the transcription landscape by providing a free, open-source model with near-commercial accuracy. It supports 100 languages, runs locally for privacy, and spawned an ecosystem of tools and services built on top of it.
Strengths and weaknesses
Strengths
- Rich audio intelligence features beyond transcription
- LLM Gateway enables Q&A on audio content
- Excellent developer documentation
- Universal-2 at $0.15/hr undercuts Deepgram Nova-3 pre-recorded ($0.0043/min, about $0.26/hr)
Weaknesses
- Universal-3.5 Pro covers 18 languages, fewer than Universal-2's 99
- Premium real-time model (Universal-3.6 Pro Realtime) costs $0.45/hr
- In-region US/EU processing costs 10% more
Strengths
- Free and open source
- Excellent multilingual accuracy
- Can run fully offline for privacy
Weaknesses
- Raw model requires technical setup
- No built-in speaker diarization
- CPU inference is slow without GPU
Try both and decide
The best way to choose is to test each tool with your own workflow. Most offer free tiers or trials.