ElevenLabs vs Cartesia

Voice Quality and Expressiveness

Eleven v4 is ElevenLabs' biggest model change in a year. It uses a new architecture, takes inline tags such as [laughs] for delivery, handles IPA pronunciation better and keeps several speakers more consistent in dialogue. ElevenLabs says listeners preferred it in about three-quarters of blind tests. Its strength is long-form, emotional narration: audiobooks, documentary voiceover, characters.

Sonic-3.6 aims for natural speech at conversational speed rather than performance. Cartesia exposes expressiveness as parameters, with roughly 60 named emotion values, a [laughter] tag and controls for speed and volume, which suits developers who want predictable output from code. Cartesia reports that listeners chose Sonic-3.6 over Eleven v3 92% of the time in US English tests. That comparison predates Eleven v4 and, like ElevenLabs' own figures, is a vendor claim.

Both companies cite first place on Artificial Analysis's speech arena. Cartesia claimed it at Sonic-3.6's launch in August, and ElevenLabs claimed it for v4 a month later. The rankings move with every release, so a buyer should listen to their own scripts in both rather than rely on either claim.

Latency and Real-Time Agents

Latency is where Cartesia built its name. Its Sonic models were built for streaming from the start, and Sonic-3.6 is marketed on first audio in under 90 ms. For a phone agent, those milliseconds decide whether a conversation feels natural or stilted, and conversational AI teams often choose Cartesia for that reason alone.

ElevenLabs has narrowed the gap. Flash v2.5 is quoted at about 75 ms of model latency in 32 languages, and v4 Turbo at about 100 ms of median inference and 150 ms to first speech. The numbers are not directly comparable, because vendors measure different points in the pipeline and network time is added in production. In practice both are fast enough for live agents; the choice turns on language coverage, voice quality at speed, and the agent platform around the model.

On that platform, ElevenAgents and Cartesia's Line both connect to telephony (SIP and Twilio) and to any large language model. ElevenAgents adds a knowledge base and tools. Line leans toward developers, with a CLI, call logs, evaluations and batch calling up to 5,000 calls.

Breadth: Beyond Text-to-Speech

ElevenLabs is far broader. Scribe v2 transcribes 90+ languages with word-level timestamps and diarization for up to 32 speakers. Its dubbing product translates video into 90+ languages while keeping each speaker's voice, which makes it a default choice for AI dubbing. Music v2.5 generates songs, and Voice Isolator strips noise from recordings. For a creator or studio, one account covers narration, transcripts, translation, music and cleanup.

Cartesia's second product is Ink-2, a streaming speech-to-text model built for agents, with turn events and "semantic endpointing" that tries to tell when a speaker has finished a thought. It covers five languages and does not advertise diarization or word timestamps, so it is a component for live agents rather than a transcription service for editing. For batch transcription, see Deepgram vs AssemblyAI.

Pricing at List

Both sell monthly credit plans. ElevenLabs runs from a free tier (10K credits) through Starter at $6, Creator at $22, Pro at $99, Scale at $299 and Business at $990 a month, with annual discounts; Flash and Turbo models cost 0.5 to 1 credit per character. Cartesia runs from free (20K credits) through Pro at $5, Startup at $49 and Scale at $299 a month, at 1 credit per character for speech.

At list prices on 2026-10-20, Cartesia's plans include more characters per dollar at every comparable tier: its $299 Scale plan carries 8 million credits against ElevenLabs' 1.8 million at the same price. ElevenLabs' credits also cover a far wider product set, and high-volume buyers on either platform negotiate enterprise terms. Neither free plan allows commercial use.

Deployment, Data and Safety

Cartesia offers more deployment choice. Sonic can run in a customer's own cloud through Baseten, Amazon SageMaker or Together AI, self-hosted Sonic-3.6 support arrived for enterprise customers in September 2026, and Line offers zero data retention on enterprise plans. That matters for call centers and regulated industries that cannot send audio to a shared API.

ElevenLabs is a hosted platform with enterprise plans. Both make instant cloning from a short sample easy (under two minutes of audio at ElevenLabs, about ten seconds at Cartesia), which brings the same voice-deepfake risk. Teams should keep a consent record for every cloned voice whichever vendor they choose.