StepFun has released StepAudio 3 ASR, ranking #1 on the AA-WER Index for non-streaming Speech to Text with 1.7% WER, a notable improvement on StepAudio 2.5 ASR (4.7%)

StepAudio 3 ASR is StepFun's new Speech to Text model, available through the StepFun API for non-streaming transcription, and the first StepFun model to reach the top of our non-streaming Speech to Text leaderboard.

Key takeaways

➤ Accuracy: StepAudio 3 ASR scores 1.7% on the AA-WER Index, effectively tied with Alibaba's Fun-Realtime-ASR-preview at 1.7%. It leads on AA-AgentTalk, our held-out voice-agent dataset, at 1.4%, but trails on long-form Earnings22 calls at 2.8%, where Fun-Realtime-ASR-preview scores 1.8%

➤ Speed: The model transcribes at a speed factor of 88x real time, behind MAI-Transcribe-2 at 374x, Smallest AI Pulse Pro at 285x and Grok Voice Transcribe 2.0 at 154x, roughly level with ElevenLabs Scribe v2 at 84x and Gemini 3.5 Transcribe at 91x, and ahead of Fun-Realtime-ASR-preview at 20x

➤ Price: StepAudio 3 ASR costs $0.40 per hour, or $6.67 per 1,000 minutes, the most expensive of the five most accurate models. MAI-Transcribe-2 and Grok Voice Transcribe 2.0 cost $1.67 per 1,000 minutes and ElevenLabs Scribe v2 $3.67, so the trade-off is top-tier accuracy on conversational audio at a higher cost per minute

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