Updated March 2026Methodology
Voice AI Benchmark Report, 2026
Independent testing across every major STT and TTS provider.
Every number cited. Every source linked. No affiliation with any provider.
STT Provider Comparison — Speko-tested providers only
| Provider | WER% | Latency | Cost/min | Languages | Noise Δ | Tested | Src |
|---|---|---|---|---|---|---|---|
| Deepgram Nova-3 | 7.8% | 2.4s | $0.0043 | 36 | +2.6pp | ✓ Speko | |
| ElevenLabs Scribe v2 Realtime | 3.5% | 1.0s | $0.0067 | 99 | +1.7pp | ✓ Speko | |
| ElevenLabs Scribe v1 | 5.4% | 1.1s | $0.0067 | 99 | +1.5pp | ✓ Speko | |
| Alibaba qwen3-asr-flash | 3.5% | 0.6s | $0.0021 | 90 | +1.9pp | ✓ Speko | |
| OpenAI gpt-4o-transcribe | 19.4% | 1.9s | $0.0060 | 50 | +2.1pp | ✓ Speko | |
| OpenAI gpt-4o-mini-transcribe | 8.2% | 2.0s | $0.0030 | 50 | +2.2pp | ✓ Speko | |
| OpenAI whisper-1 | 11.6% | 2.6s | $0.0060 | 57 | +2.7pp | ✓ Speko | |
| xAI Grok STT | 16.75% | 0.9s | $0.0017 | 25 | +-0.6pp | ✓ Speko | |
| AssemblyAI Universal-2 | 6.22% | 3.7s | $0.0062 | 99 | +1.7pp | ✓ Speko | |
| AssemblyAI Universal-3 Pro | 5.06% | 4.2s | $0.0067 | 6 | +-0.0pp | ✓ Speko | |
| Google Cloud Chirp 2 | 5.37% | 4.5s | $0.0240 | 125 | +12.6pp | ✓ Speko | |
| Google Gemini 2.5 Flash (STT) | 6.03% | 2.5s | $0.0002 | 100 | +12.9pp | ✓ Speko |
Disclaimer: STT WER, latency, noise robustness, and multi-language data are independently tested by Speko using automated benchmarks. Pricing reflects publicly available rates. TTS, LLM, S2S, and platform data sourced from official documentation. We are not affiliated with any provider listed.
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