ElevenLabs vs OpenAI TTS: Which One''s Right for You?
If you're picking between ElevenLabs and OpenAI text-to-speech models for your next voice agent build, you probably want to know about speed, cost, and customization:
Both providers are excellent; they just do different things well. When building in Vapi, you can test them for yourself: OpenAI TTS and ElevenLabs Turbo and Flash models are built-in.
This comparison article gives some more essential information before you go and see for yourself.
» Learn more about TTS technology here.
In TTS, everyone talks about latency. ElevenLabs Flash v2.5 achieves an ultra-low latency of 75ms; that’s lightning-fast. OpenAI comes in at 200ms, which seems glacial in comparison, but it’s really not. Between the two models, we’re talking about a difference of 125ms, about one human blink. Most of your users won’t notice.
For some builds, speed is everything, but for many, 200ms is plenty quick. You also need to think about word accuracy, natural-sounding voices, error rates, and cost. You'd probably trade a few ms for a voice agent that gets things right.
Here’s a top-line comparison:
| Features | ElevenLabs | OpenAI | Does It Matter? |
|---|---|---|---|
| First Audio Time | 75ms (Flash v2.5) / 150ms (standard) | 200ms | Sometimes (realtime applications) |
| Word Accuracy | 82% | 77% | Yes, and both are pretty good |
| Natural Sound | 45% rated high | 22% rated high | Yes, but depends on your use case |
| Error Rate | 2.8% | 3.4% | Both work fine |
| Cost (1M chars) | $165$330+ | $15 | OpenAI is cheaper |
So, OpenAI is cheaper to use, but ElevenLabs is faster and sounds more natural. For accuracy, there isn't much in it. Let's dive a little deeper:
ElevenLabs built their Flash models specifically for speed. Their Flash v2.5 model achieves ultra-low 75ms latency optimization, and it shows. If you're building something where every millisecond counts (like live customer support or real-time conversations), this focus pays off.
OpenAI took a different route. Instead of pure speed, they built everything into one API call. Speech recognition, processing, voice synthesis. It all happens together. That adds latency compared to ElevenLabs' specialized approach, but it makes your code way simpler. No juggling multiple services or handling handoffs between systems.
Go with ElevenLabs when speed directly affects your user experience, like in customer support scenarios where people expect instant responses. Go with OpenAI when you want simple integration, and the latency difference won't hurt your users, or you're building smart device integrations that need everything in one package.
OpenAI keeps it simple. You pay for what you use. Regular TTS costs $15 per million characters, the HD version runs $30 per million, and their Mini model comes in at $0.60 per million input characters.
ElevenLabs goes with monthly subscription plans. The Starter plan gives you 30k characters for $5 monthly. Need more? The Creator plan bumps you to 100k characters for $22. Heavy users can grab the Pro plan at $99 for 500k characters, or go big with the Scale plan at $330 for 2 million characters.
If you're using 50k characters monthly, OpenAI costs you 75 cents while ElevenLabs requires the Creator plan at $22 (since the $5 Starter plan only covers 30k characters). Bump up to 500k characters monthly and OpenAI hits $7.50 while ElevenLabs charges $99 for the Pro plan (but includes voice cloning and better support). At 2 million characters monthly, OpenAI costs $30 while ElevenLabs charges $330 for their Scale plan with all the bells and whistles.
Pick OpenAI when you're just getting started, usage is unpredictable, or you want the cheapest option. Choose ElevenLabs when you need the premium features anyway, want predictable bills, or you're doing enough volume that the extra features justify the cost.
» Learn how Vapi keeps price simple and scalable, for both models.
Both platforms sound great, but in different ways. When it comes to this TTS solution comparison, it's like comparing a perfectly tuned sports car to a reliable luxury sedan. Both excellent, just optimized for different things.
ElevenLabs focuses on natural-sounding speech with more accurate pronunciation (82% vs 77%) and better emotional expression. They deliver studio-quality audio output and excel at natural flow and prosody.
OpenAI prioritizes consistency across different content types with super clean audio that has less background noise. They focus on clarity over pure naturalness and just work without tweaking. Their approach means reliable, predictable quality no matter what you throw at them.
The honest truth? Most people won't notice a huge difference unless they're listening side-by-side. Voice preference is really personal and depends on your content.
Go with ElevenLabs when voice quality is part of your brand, you need emotional expression, or you're creating content where "sounding human" matters most. Go with OpenAI when you want reliable, consistent quality without thinking about it, or when clear communication matters more than perfect naturalness.
» Speak to a demo custom agent here.
This is probably the biggest difference between the two platforms.
ElevenLabs gives you everything. You get 3,000+ different voices to choose from, can clone any voice with just a short sample, and tweak pitch, speed, and emotion; the world’s your oyster. They even have support for unique voices that other platforms struggle with.
OpenAI keeps it simple with 11 really well-crafted voices. No customization needed (or possible). You pick one and you're done. No voice data to manage, no endless options to wade through.
Think of it like choosing between a professional audio studio and a high-end podcast setup. The studio has every tool imaginable, but the podcast setup just nails the essentials.
So, ElevenLabs for when you need a specific brand voice, want unique audio identity, or customization options matter for your use case. OpenAI for when you want simplicity over options, don't want to manage voice data, or prefer "it just works".
ElevenLabs supports 32 languages with different voice options for each. Great if you're creating content for specific markets and want voices that sound right for each culture. OpenAI handles multiple languages smoothly in the same conversation, perfect if you need seamless language switching without complexity.
Go with ElevenLabs when you're creating localized content for different markets or need culturally appropriate voices. Opt for OpenAI when you want simple multilingual support or need dynamic language switching in conversations.
Normally, this would be a big deal. With Vapi, it’s not. ElevenLabs and OpenAI come built-in to our platform. When you begin your project, simply choose which model you want your voice agent to use. No heavy lifting, no added complexity. Just start building.
» Check out how Vapi makes it easy.
If you didn’t click the link above, or you’re still unsure, here's how to decide:
For real-time conversations, ElevenLabs wins if every millisecond counts (customer service, live chat, phone systems). At the same time, OpenAI works better if you need integrated features, and the latency difference won't hurt the experience. You’ll know what is best here.
For budget-conscious projects, OpenAI is almost always the more cost-effective option, especially when starting out. ElevenLabs only makes sense if you need the premium features.
For brand and content work, ElevenLabs excels when voice is an integral part of your brand identity. OpenAI works great when you want good voices without the complexity.
For development, ElevenLabs gives you control over every component, whereas OpenAI makes everything easily work together.
The smart move? Test both with your actual content and users. What works for someone else might not work for you.
Here's what most people miss. You don't have to choose just one. Elevenlabs and OpenAI TTS models are built into the Vapi platform, ready to go. You can test both, optimize for different use cases and conditions, and even scope out some alternatives.
You can route premium customers to ElevenLabs for the best voice quality while sending high-volume, cost-sensitive users to OpenAI. Different content types can be directed to the platform that handles them better, and you can A/B test to see what your users prefer.
This approach gives you the best of both worlds without the commitment, providing real data on what works for your users, lower costs by utilizing each platform where it excels, and a future-proof setup as both platforms continue to improve.
Both ElevenLabs and OpenAI are excellent choices. They just excel at different things. The real win isn't picking the "best" platform, it's having the flexibility to use the right tool for each job. Enter Vapi.
» Decide for yourself on Vapi - Sign Up and Get Building.
\
