Terms of Use

1. Acceptance of terms

By accessing and using this website (“TTS API Cost Calculator”), you accept and agree to be bound by these Terms of Use. If you do not agree, do not use this site. This site is operated by DayOne Labs Ltd (Company No. 17192046), registered in England and Wales.

2. Nature of the service

This tool provides estimates of text-to-speech API costs based on publicly available pricing documentation from third-party providers. It also displays comparative metrics for voice quality, latency, and language support sourced from public benchmarks. It is designed for informational and comparison purposes only.

3. Pricing accuracy disclaimer

All cost estimates are approximations. Actual costs may differ due to:

• Provider pricing changes not yet reflected in our data
• Volume discounts, enterprise agreements, or promotional offers
• Character counting differences between providers (e.g. treatment of whitespace, SSML tags, Unicode)
• Overage charges, minimum fees, or per-request surcharges
• Currency conversion or regional pricing variations
• Free tier credits, trial periods, or prepaid balances

Always verify pricing directly with the provider before making purchasing decisions. We make reasonable efforts to keep pricing data current but provide no guarantee of accuracy.

4. Benchmark data and methodology

In addition to cost data, this site displays comparative metrics for voice quality, latency, and language support. These are sourced as follows:

• Quality scores are derived from publicly available crowd-sourced benchmarks, including the Artificial Analysis Speech Arena (Elo-based blind A/B testing) and Mean Opinion Score (MOS) evaluations. Scores are normalised to a 1–5 scale for comparison. They reflect general voice naturalness and are not provider-endorsed ratings.
• Latency figures represent typical P50 (median) time-to-first-audio (TTFA) in milliseconds, sourced from published provider specifications, independent benchmarks, and third-party evaluations. Actual latency varies by model, region, input length, and network conditions.
• Language counts are sourced from each provider's official documentation and may include regional variants or dialects depending on how the provider defines a “language.” Counts are updated periodically but may lag behind real-time documentation.

Benchmark data is indicative, not definitive. We do not conduct our own testing. All data is sourced from publicly available third-party evaluations and official provider documentation. Rankings and scores may change as providers update their models and infrastructure. This data should not be the sole basis for procurement decisions.

5. Official pricing sources

All cost calculations are derived from the following official pricing pages, last verified 23 June 2026. We encourage you to check these directly before making purchasing decisions.

6. No affiliation or endorsement

This site is not affiliated with, endorsed by, or sponsored by any of the text-to-speech providers listed. All product names, logos, and trademarks are the property of their respective owners. Their inclusion on this site is for identification and comparison purposes only and does not imply any endorsement or partnership.

7. Affiliate links and advertising

This site may contain affiliate links. If you click through and make a purchase or sign up for a service, we may receive a commission at no additional cost to you. Affiliate relationships do not influence the pricing calculations or benchmark data displayed on this site. All calculations are derived from the same published API pricing data regardless of whether an affiliate relationship exists with a given provider.

This site also displays third-party advertisements. We are not responsible for the content, accuracy, or practices of advertised products or services.

8. Limitation of liability

To the fullest extent permitted by law, DayOne Labs Ltd shall not be liable for any direct, indirect, incidental, consequential, or special damages arising from your use of or reliance on this tool, including but not limited to financial losses resulting from inaccurate cost estimates or benchmark data.

This tool is provided “as is” and “as available” without warranties of any kind, whether express or implied, including but not limited to implied warranties of merchantability, fitness for a particular purpose, and non-infringement.

9. Your content

Text you enter into the calculator is processed entirely within your browser. We do not collect, store, transmit, or have access to any text you paste. You are solely responsible for ensuring you have the right to use any content you enter.

10. Intellectual property

The design, code, and original content of this website are © 2026 DayOne Labs Ltd. You may not reproduce, distribute, or create derivative works from this site without written permission.

11. Governing law

These terms are governed by and construed in accordance with the laws of England and Wales. Any disputes shall be subject to the exclusive jurisdiction of the courts of England and Wales.

12. Changes to these terms

We reserve the right to modify these terms at any time. Continued use of the site after changes constitutes acceptance of the revised terms.