Cartesia vs ElevenLabs
Discover key differences between Cartesia and ElevenLabs voice AI models.
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Compare Cartesia and ElevenLabs Voice AI Models
Sonic outperforms ElevenLabs Flash V2 with better voice naturalism (61.4% preference in blind tests), faster performance (40ms vs 75ms model latency), and superior features including instant voice cloning (3s vs 30s audio required) and comprehensive voice delivery controls.
Updated on:
Feb 24, 2025
Features
Cartesia
40ms for the Sonic Turbo model, 90ms for the Sonic 2.0 model
Consistently rated as more natural, expressive, and realistic in blinded human evaluations
Infinite request length
Requires 3 seconds of audio
IPA support with strong contextual understanding
Fully customizable voice with speed and emotion controls + synthetic voice mixing and design
8kHz audio, telephony optimized voices
Supports both on-prem and on-device deployments
15 languages with extensive dialect coverage
Up to 15 on highest self-serve tier (60 parallel conversations), custom for enterprise
ElevenLabs
75 ms for the lower quality Flash Model, and 300ms+ for the full model
Less depth and reliability ratings in human evals
Limited to 40k characters per request
Requires 10 seconds of audio
Requires 60 minutes of audio
IPA support, isolated pronunciation
Stability, similarity, and style exaggeration controls
8kHz audio, telephony optimized voices
No on-device or on-prem support
32
Up to 15 on highest self serve tier, custom for enterprise
Cartesia - Faster and More Natural Voices
Cartesia AI offers the fastest voice model with hallucination-free, ultra-realistic voice generation and cloning.
High-Quality Voice Cloning
Cartesia's voice cloning delivers lifelike, accurate voice replication with unmatched fidelity, only requires 3 seconds of audio.
Ultra-Realistic Voices
With a model latency of just 40ms, Sonic provides the fastest and most realistic voice generation available.
No Hallucinations
Cartesia's AI text to speech eliminates errors, accurately follow complex transcripts like names, addresses, time, medical terms. etc.
Enterprise Ready
Enterprise-grade reliability with 99.9% uptime, SOC2 compliance, and full on-premises support.
Voice Quality
In head-to-head evaluations, our blinded human tests showed that Sonic-2 was preferred over ElevenLabs's Flash V2 model by a significant margin (61.4% vs 38.6%).
Blinded human evaluation is a method where evaluators assess generative voice model outputs without knowing which model produced them, helping reduce bias. The process involves presenting outputs from different generative voice model anonymously. This approach prevents evaluators' preconceived notions about specific generative voice model or their developers from influencing their assessment.
Latency
We measure latency using the model latency and the Time to First Audio (TTFA) latency from Asia, US and Europe. We calculate the 90th percentile score (P90) from 100 measurements for each provider.
Cartesia's Sonic-2 model achieves a model latency of just 40ms—significantly faster than ElevenLabs' Flash V2 model at 75ms. P90 latency measurements across all three locations demonstrate Cartesia's consistent performance advantage over ElevenLabs. While Cartesia maintains stable latency between 128-135ms, ElevenLabs' latency fluctuates widely from 264ms to 531ms.
This superior performance comes from Cartesia's Sonic model using State Space Models (SSMs), which provide a more efficient architecture for latency optimization than the traditional transformer architecture used by ElevenLabs and other providers.
Pronunciation Accuracy
Cartesia and ElevenLabs exhibit slight differences in sentence pronunciation. Cartesia excels at accurately pronouncing challenging content, such as acronyms, phone numbers, and uncommon words, and supports the International Phonetic Alphabet (IPA) for specialized use cases, like prescription drug names in healthcare. While ElevenLabs also offers reasonably accurate pronunciation, it shows less contextual awareness.
Example #1
For example, when pronouncing an abbreviated date like "Dec. 25, 2022," Cartesia delivers a more human-like pronunciation of "December," whereas ElevenLabs tends to interpret it more literally.
Cartesia
ElevenLabs
Voice Cloning
Cartesia requires only 3 seconds of audio recording to create high-quality instant voice clones, while ElevenLabs needs 30 seconds.
Cartesia offers unlimited instant voice cloning in the paid plans, whereas ElevenLabs limits cloning in tiered plans that allow 10, 30, 160, or 660 custom voices.
Cartesia's advanced embedding technology delivers consistent, high-quality voice clones, preserving accents and voice quality even with noisy source audio. With its voice mixing and design capabilities, Cartesia creates a more comprehensive range of diverse voices. The following samples of Engelbart's clones demonstrate how Cartesia produces clearer, higher-quality clones compared to ElevenLabs.
Example #1
Example with noisy background.
Cartesia better matches the original voice as well as the surrounding recording environment
ElevenLabs struggles to separate background noise from human voices, resulting in lower-quality voice clones.
Source
Cartesia
ElevenLabs
Example #2
Example with Reporter in Wildfire
Cartesia better preserves the accent and the surrounding recording environment
Source
Cartesia
ElevenLabs
Voice Design Controllability
Cartesia stands out as the only provider offering emotion and speed modulation features, enabling refined voice adjustments while preserving a natural and seamless auditory experience.
Cartesia also allows you to localize the voice to match different accents — you can start with an American voice and have it speak in a French accent, for instance. In comparison, ElevenLabs only offers controls for stability, similarity, and style exaggeration, all of which do not offer clear control for the voice.
In the following example where the speaker is addressing a customer complaint, we compare the dial effects from ElevenLabs and Cartesia to find that the ElevenLabs voice sounds similar with the various dials applied while Cartesia's emotion and speed dials convey very noticeable changes.
Cartesia
No Dials
ElevenLabs
No Dials
Cartesia
Positivity Emotion Dial
ElevenLabs
Highest Stability Dial
Cartesia
Speed Dial
ElevenLabs
Highest Similarity Dial
Pricing Plans for Cartesia and ElevenLabs
Cartesia
Free - $0 per month with 10k free credits
Pro - $5 per month with 100k credits
Startup - $49 per month with 1.25M credits
Scale - $299 per month with 8M credits
Enterprise - trusted by Fortune 500 companies
ElevenLabs
Free - $0 per month with 10k characters
Starter - $5 per month with 30k characters
Professional - $11 per month with 100k characters
Pro - $99 per month with 500k characters
Scale - $330 per month with 2M characters
What Cartesia Customers Say
Join the growing list of companies opting for Sonic.
"Cartesia’s voice API power dynamic and empathetic conversational experiences that are consistently dependable. What really stands out to me is how natural and considerate the responses feel—especially the empathetic tone in statements like ‘I’m sorry, that must be frustrating.’"
Sami Ghoche, CEO of Forethought
"In 1999, Salesforce brought software to the cloud. In 2025, 11x is killing software as we know it and unleashing the era of digital workers. To realise this vision, we needed AI voice technology that feels truly human. Cartesia’s technology gives our AI digital workers reps the speed, reliability, and natural expressiveness required to engage customers at scale.
It's the only solution fit for our relentless drive toward innovation.”
Keith Fearon, Head of Product & Growth, 11x
"Before conversational voice models like Cartesia, Thoughtly relied on legacy text-to-speech APIs from major cloud providers. Nearly two years later, the evolution of this technology is staggering—customers can clone their voice and hear it speaking autonomously over the phone in just 60 seconds.”
Torrey Leonard, CEO, Thoughtly
