Voice AI latency statistics (2026): measured on real phone calls
Median voice AI agent reply times on real phone calls: 1.04 s to 1.86 s across 8 platforms (89 calls). Free chart, CSV (CC BY 4.0) and citation.
On real phone calls, the fastest agents answered in a median 1.04 s; the slowest took 1.86 s. That is 89 calls and 270 turns in total, so treat small gaps as noise.
- 1.04 s–1.86 smedian reply time on real phone calls, 8 platforms
- 0.41 s–1.15 smedian in a browser connection, 4 platforms (41 calls)
- +0.28 s to +0.69 sadded by the phone line, for the 4 platforms tested both ways
Retell AI1.04 s
ElevenLabs Agents1.04 s
Ultravox1.18 s
Millis AI1.25 s
OpenAI Realtime API1.52 s
LiveKit Agents1.52 s
Vapi1.56 s
Bland AI1.86 s
| Platform | Phone median | Phone p90 | Calls | Turns | Browser median |
|---|---|---|---|---|---|
| Retell AI | 1.04 s | 1.22 s | 11 | 33 | 0.76 s |
| ElevenLabs Agents | 1.04 s | 1.34 s | 11 | 33 | 0.41 s |
| Ultravox | 1.18 s | 1.55 s | 11 | 33 | 0.49 s |
| Millis AI | 1.25 s | 2.00 s | 12 | 36 | not tested |
| OpenAI Realtime API | 1.52 s | 2.00 s | 11 | 35 | not tested |
| LiveKit Agents | 1.52 s | 2.14 s | 11 | 33 | not tested |
| Vapi | 1.56 s | 1.83 s | 11 | 34 | 1.15 s |
| Bland AI | 1.86 s | 2.02 s | 11 | 33 | not tested |
Reply time is measured from the end of the caller's audio to the start of the agent's reply, on each vendor's default setup, from Ashburn, Virginia. Rounds 2 and 3, October 20, 2026. Every platform shown had at least 10 completed calls.
Use this data
Free to reuse under CC BY 4.0: credit Cozzo and link here.
Cite this (APA)
Cozzo. (2026, October 20). Voice AI agent latency on real phone calls [Data set]. https://cozzo.io/stats/voice-ai-latencyCite this (link / HTML)
<a href="https://cozzo.io/stats/voice-ai-latency">Voice AI agent latency on real phone calls</a> (Cozzo, 2026)Embed this chart
<a href="https://cozzo.io/stats/voice-ai-latency"><img src="https://cozzo.io/stats/voice-ai-latency/chart.svg" alt="Voice AI agent latency on real phone calls. Source: Cozzo" width="680" style="max-width:100%;height:auto"></a>
<p>Source: <a href="https://cozzo.io/stats/voice-ai-latency">Cozzo</a> (CC BY 4.0)</p>Methodology and sources
FAQ
- How fast do voice AI agents reply on a phone call?
- In Cozzo's tests the median reply time on real phone calls ranged from 1.04 s to 1.86 s across 8 platforms (89 calls, 270 turns, October 20, 2026).
- Why is phone latency higher than browser latency?
- The phone network adds time. For the 4 platforms we tested both ways, the phone median was 0.28 s to 0.69 s slower than in a browser connection.
- How big is the sample?
- At least 10 calls per platform, 89 calls in total, on default settings. Small differences between platforms may be noise.