Voice AI BenchmarksBy

PROVIDERLAST 30 DAYS

official resource

Google voice AI models and benchmarks

Google lists 5 STT, TTS and S2S models in Coval. Fastest dated mean latency over 30 days: STT: Gemini 3.5 Transcribe Live on Gemini at 317 ms TTFS. TTS: Chirp 3 HD at 597 ms TTFA. Coval benchmarks hosted endpoints daily using a consistent evaluation methodology. Last measured .

Google creates and hosts voice models across all three benchmark categories: Cloud Speech-to-Text, Cloud Text-to-Speech and the native-audio Gemini Live API.

Measured models
5
STTTTSS2S
Best STT model#21 / 29
317ms
Gemini 3.5 Transcribe Live
Best TTS model#29 / 32
597ms
Chirp 3 HD

Overview

Google ships voice models across STT, TTS and S2S; each product and generation is ranked separately in its own category.

Every model below is measured daily on the same fixed inputs and ranked against the full field, never blended into a company score.

Model lineup

Speech-to-Text
Gemini 3.5 Transcribe Live, Chirp 2, Chirp 3
Text-to-Speech
Chirp 3 HD
Speech-to-Speech
Gemini 3.1 Flash Live (Preview)

Speech-to-Text

Full STT dashboard

Ranked on Time to Final Segment against 29 measured models.

Time to Final Segmentms · lower is better · Google models markedEvery measured STT model on Time to Final Segment, with Google's models highlighted.
  1. #1Qwen3 ASR 1.7b39 ms
  2. #2STT RT v545 ms
  3. #3Qwen3 ASR Fast47 ms
  4. #4STT 167 ms
  5. #5Nova 385 ms
  6. #6Nova 287 ms
  7. #7Parakeet TDT 0.6B v397 ms
  8. #21Gemini 3.5 Transcribe Live317 ms
  9. #27Chirp 3768 ms
  10. #29Chirp 2908 ms
leaders plus Google models · 19 other models in the full table
Word Error Rate% · lower is better · Google models markedEvery measured STT model on Word Error Rate, with Google's models highlighted.
  1. #1Universal 3.6 Pro2.1%
  2. #2Universal 3.5 Pro2.3%
  3. #3Qwen3 ASR Fast2.6%
  4. #4resonant-12.6%
  5. #5Qwen3 ASR 1.7b2.9%
  6. #6Gemini 3.5 Transcribe Live3.0%
  7. #7Chirp 33.2%
  8. #10Chirp 23.9%
leaders plus Google models · 23 other models in the full table
Time to First Tokenms · lower is better · Google models markedEvery measured STT model on Time to First Token, with Google's models highlighted.
  1. #1Whisper Large v3via Baseten924 ms
  2. #2Qwen3 ASR 1.7b946 ms
  3. #3Universal 3.5 Pro1026 ms
  4. #4Universal 3.6 Pro1072 ms
  5. #5Flux1091 ms
  6. #6Flux Multilingual1165 ms
  7. #7STT 11208 ms
  8. #16Gemini 3.5 Transcribe Live1606 ms
  9. #26Chirp 35956 ms
  10. #27Chirp 26099 ms
leaders plus Google models · 17 other models in the full table
TTFS vs WER — Google vs every measured modelEach point is one measured STT model · Google models highlighted · 30-day averagesTime to Final Segment against Word Error Rate for every measured STT model, with Google's models highlighted.
Qwen3 ASR 1.7b — 39 ms, 2.9%STT RT v5 — 45 ms, 4.8%Qwen3 ASR Fast — 47 ms, 2.6%STT 1 — 67 ms, 7.1%Nova 3 — 85 ms, 5.3%Nova 2 — 87 ms, 6.7%Parakeet TDT 0.6B v3 — 97 ms, 11.1%Flux Multilingual — 98 ms, 7.5%Flux — 99 ms, 5.8%Scribe v2 Realtime — 122 ms, 4.4%Whisper Large v3 via Baseten — 131 ms, 4.5%Universal 3.6 Pro — 135 ms, 2.1%Ink 2 — 149 ms, 3.6%Universal 3.5 Pro — 168 ms, 2.3%Whisper Large v3 via Together AI — 199 ms, 7.4%Pulse — 205 ms, 4.6%Grok STT — 223 ms, 4.1%resonant-1 — 252 ms, 2.6%Default — 258 ms, 8.8%Linden 1 — 271 ms, 3.9%Daytona STT — 399 ms, 4.9%Voxtral Mini Transcribe Realtime 2602 — 411 ms, 5.3%GPT Realtime Whisper — 599 ms, 4.0%Solaria 1 — 626 ms, 6.0%GPT-4o mini Transcribe — 708 ms, 3.9%GPT-4o Transcribe — 783 ms, 3.7%Gemini 3.5 Transcribe Live — 317 ms, 3.0%Chirp 3 — 768 ms, 3.2%Chirp 2 — 908 ms, 3.9%
Benchmarked models with their Time to Final Segment over the last 30 days.
ModelHostTTFSRank
Gemini 3.5 Transcribe LiveGemini317 ms21st of 29
Chirp 2Google908 ms29th of 29
Chirp 3Google768 ms27th of 29

Text-to-Speech

Full TTS dashboard

Ranked on Time to First Audio against 32 measured models.

Time to First Audioms · lower is better · Google models markedEvery measured TTS model on Time to First Audio, with Google's models highlighted.
  1. #1vui60 ms
  2. #2Default63 ms
  3. #3Qwen3 TTS Fast68 ms
  4. #4TTS Flash 291 ms
  5. #5Qwen3 TTS 1.7b107 ms
  6. #6Simba 3.0111 ms
  7. #7Palabra TTS v1120 ms
  8. #29Chirp 3 HD597 ms
leaders plus Google models · 24 other models in the full table
Word Error Rate% · lower is better · Google models markedEvery measured TTS model on Word Error Rate, with Google's models highlighted.
  1. #1Sonic 3.61.5%
  2. #2S2.1 Pro Free1.5%
  3. #3Simba 3.01.5%
  4. #4S2.1 Pro1.5%
  5. #5Lightning v3.1 Pro1.5%
  6. #6Sonic 3.51.5%
  7. #7Chirp 3 HD1.5%
leaders plus Google models · 25 other models in the full table
TTFA vs WER — Google vs every measured modelEach point is one measured TTS model · Google models highlighted · 30-day averagesTime to First Audio against Word Error Rate for every measured TTS model, with Google's models highlighted.
vui — 60 ms, 2.1%Default — 63 ms, 1.9%Qwen3 TTS Fast — 68 ms, 1.8%TTS Flash 2 — 91 ms, 1.7%Qwen3 TTS 1.7b — 107 ms, 1.8%Simba 3.0 — 111 ms, 1.5%Palabra TTS v1 — 120 ms, 2.6%Simba 3.2 — 126 ms, 1.9%drama3-preview — 168 ms, 2.0%TTS 2 — 191 ms, 1.6%Flash v2.5 — 191 ms, 1.8%Eleven v4 Turbo — 201 ms, 1.7%Flux TTS — 205 ms, 1.7%TTS RT v1 — 254 ms, 2.4%TTS Rt v2 — 256 ms, 2.4%Mist v3 — 287 ms, 2.1%Sonic 3.5 — 293 ms, 1.5%Phantom Z 3.4 conversational — 293 ms, 1.8%Aura 2 — 297 ms, 1.8%Sonic 3.6 — 299 ms, 1.5%Falcon 2 — 301 ms, 1.7%Coda — 332 ms, 9.5%S2.1 Pro — 341 ms, 1.5%Grok TTS — 362 ms, 1.6%S1 — 389 ms, 1.8%Lightning v3.1 Pro — 393 ms, 1.5%Daytona TTS — 486 ms, 1.6%Aura 2 En — 570 ms, 2.1%Qwen3 TTS Flash Realtime — 718 ms, 3.0%S2.1 Pro Free — 850 ms, 1.5%GPT-4o mini TTS — 2581 ms, 1.8%Chirp 3 HD — 597 ms, 1.5%
Benchmarked models with their Time to First Audio over the last 30 days.
ModelHostTTFARank
Chirp 3 HDGoogle597 ms29th of 32

Speech-to-Speech

Full S2S dashboard

Ranked on Voice-to-Voice Latency.

Benchmarked models with their Voice-to-Voice Latency over the last 30 days.
ModelHostV2VRank
Gemini 3.1 Flash Live (Preview)Googleno measurements this window

How fast are Google's STT, TTS and S2S models?

Gemini 3.5 Transcribe Live on Gemini measures mean 317 ms time to final segment (21st of 29) among STT systems. Last measured 2026-10-14. Chirp 3 measures mean 768 ms time to final segment (27th of 29) among STT systems. Last measured 2026-10-14. Chirp 2 measures mean 908 ms time to final segment (29th of 29) among STT systems. Last measured 2026-10-14. Chirp 3 HD measures mean 597 ms time to first audio (29th of 32) among TTS systems. Last measured 2026-10-14. No dated, ranked S2S latency is available in this window.

How accurate are Google's STT, TTS and S2S models?

Gemini 3.5 Transcribe Live on Gemini measures 3.0% word error rate (6th of 31) among STT systems. Last measured 2026-10-14. Chirp 3 measures 3.2% word error rate (7th of 31) among STT systems. Last measured 2026-10-14. Chirp 2 measures 3.9% word error rate (10th of 31) among STT systems. Last measured 2026-10-14. Chirp 3 HD measures 1.5% word error rate (7th of 32) among TTS systems. Last measured 2026-10-14. No dated, ranked S2S instruction adherence is available in this window.

Which Google model is fastest?

Its fastest dated STT result is Gemini 3.5 Transcribe Live on Gemini at mean 317 ms time to final segment (21st of 29) among STT systems, with 3.0% WER. Last measured 2026-10-14. Its fastest dated TTS result is Chirp 3 HD at mean 597 ms time to first audio (29th of 32) among TTS systems, with 1.5% WER. Last measured 2026-10-14.

Limits of this comparison

  • The measured endpoints do not represent every Google Cloud region, Chirp voice, Gemini capability or language.

Official resources

Same datasets, prompts and metric definitions for every model, measured by Coval’s open-source runner. Full methodology on the overview.

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