Cartesia vs OpenAI
Listeners rate Cartesia ahead of OpenAI's Realtime model.
Cartesia gives you the voice listeners picked, with first audio in under 90ms, voice cloning from 10 seconds, and deployment inside your own network.
Voice quality
Listeners prefer Sonic 3.6 over GPT-Realtime-2
- The Provider Voice Arena rates every model on its own voices, so a catalogue counts alongside the acoustics.
- Sonic 3.6 leads GPT-Realtime-2 there, and it is first on the Artificial Analysis Controlled Voice Arena, which holds the voice constant across every model.
Provider Voice Arena Elo
Higher is better
August 2026
1282
1070
Price
Cartesia costs a quarter of what the Realtime model does
- Artificial Analysis prices every model on the board the same way, per million characters of text.
- The cheaper model here is also the one listeners rate higher, so the saving does not come out of quality.
Price per 1M characters
USD, lower is better
August 2026
49
191.56
Reasons why companies choose Cartesia over OpenAI
Sonic 3.6
GPT-Realtime-2
CartesiaOpenAI
Human-like naturalness
Intonation, pacing, pronunciation, emotion, and audio quality that drive higher completion rates
Cartesia1282 EloOpenAI1070 EloAugust 2026
Custom voices
How much audio it takes, and who is allowed to use one.
CartesiaInstant clone from 10 seconds, professional clone from 30 minutesOpenAICustom voices are limited to eligible customers and arranged through salesDeployment
Decides whether regulated teams can use it at all.
CartesiaVPC, on-prem, on-device, or air-gapped, backed by a 99.9% uptime SLAOpenAIHosted API onlyEnd-to-end stack
How many vendors it takes to run one call.
CartesiaTTS, STT, and Agents from one vendor, on one APIOpenAITTS and Realtime speech-to-speech
Frequently asked questions
Get started today
Talk to an expert.
Connect with a member of our team and learn how Cartesia can help you build world-class voice experiences.
Start building.
Access our models via API and bring a voice agent into production in minutes.