Last updated: March 2026
NightCurve is a blood alcohol content (BAC) estimation tool that uses the Widmark formula to provide approximate calculations based on user-provided data (weight, age, biological sex, and drink information). The app also provides hangover risk estimation, drink history, statistics, an Apple Watch companion, and Live Activities for your Lock Screen.
NightCurve is available in a free version and a premium version with additional features (statistics, history, hangover risk tracking, Apple Watch).
NightCurve is NOT a medical device. It is NOT approved, cleared, or regulated by the FDA (USA), EMA (EU), TGA (Australia), or any other health regulatory authority worldwide. The app does NOT provide medical advice, diagnosis, or treatment. It is intended for educational and informational purposes only. Always consult a qualified healthcare professional for medical advice.
NightCurve provides ESTIMATES ONLY based on the Widmark formula, a simplified mathematical model. Actual BAC can vary significantly (by 20% or more) from estimates. The app CANNOT account for individual factors including but not limited to:
A BAC reading of 0.00 in the app does NOT guarantee sobriety or fitness to drive. Any BAC thresholds, region settings, legal-limit indicators, or similar references shown in the app are provided for general informational and educational purposes only. They may be simplified, incomplete, outdated, or inapplicable to your exact jurisdiction or circumstances.
Legal BAC limits vary by country, state, province, and region and may change over time. The app is NOT a substitute for a certified breathalyzer, blood test, legal advice, or official government guidance.
You assume ALL risk associated with decisions made after consuming alcohol.
The app does NOT provide legal advice. BAC estimates are NOT legal measurements and cannot be used in legal proceedings. The app cannot determine whether you are legally intoxicated or legally permitted to drive in any jurisdiction. Consult official government sources or qualified legal counsel for questions about alcohol-related laws.
Hangover risk estimates are approximate and for informational purposes only. Individual responses to alcohol vary dramatically. The app cannot predict actual hangover severity.
You must be of legal drinking age in your jurisdiction to use this app (21 in the USA, 18 in most other countries). By using NightCurve, you confirm and warrant that you meet this requirement. If you do not meet the age requirement, you must immediately cease using the app.
By using NightCurve, you acknowledge and agree that:
NightCurve offers premium features available through in-app purchases:
All payments are processed by Apple through the App Store and are subject to Apple's Terms of Service. Monthly subscriptions automatically renew unless cancelled at least 24 hours before the end of the current period. You can manage or cancel subscriptions in your Apple ID account settings. Refund requests must be directed to Apple, not to the developer. Premium feature offerings may change over time.
Nothing in these Terms affects your statutory rights as a consumer under applicable law, including mandatory consumer protection rights under EU, UK, or Australian law that cannot be excluded or limited.
Our total aggregate liability shall not exceed the amount you have paid for the app.
Some jurisdictions do not allow the exclusion or limitation of certain damages. If these laws apply to you, some or all of the above exclusions or limitations may not apply, and you may have additional rights.
You use this app entirely at your own risk.
You agree to indemnify, defend, and hold harmless NightCurve and its developers from any claims, damages, losses, costs, or expenses (including reasonable legal fees) arising from:
All content, design, code, trademarks, and trade dress in NightCurve are protected by copyright and intellectual property laws. You are granted a limited, non-exclusive, non-transferable license to use the app for personal, non-commercial purposes. You may not copy, modify, distribute, reverse-engineer, decompile, or create derivative works of any part of the app.
You acknowledge that these Terms are between you and the developer of NightCurve, not Apple. Apple has no obligation to furnish maintenance or support services for the app. In the event of a failure to conform to any applicable warranty, you may notify Apple for a refund of the purchase price; Apple has no other warranty obligation. Apple is not responsible for addressing any claims related to the app. Apple and its subsidiaries are third-party beneficiaries of these Terms and, upon your acceptance, have the right to enforce them.
These Terms are governed by and construed in accordance with the laws of Poland, without regard to conflict of law principles. For EU consumers, mandatory consumer protection laws of your country of residence may also apply.
EU users may utilize the EU Online Dispute Resolution platform: ec.europa.eu/consumers/odr
We reserve the right to terminate or suspend your access to the app at any time, for any reason, without notice. You may terminate by deleting the app. The following sections survive termination: Disclaimers (Section 2), Warranty Disclaimer (Section 6), Limitation of Liability (Section 7), Indemnification (Section 8), and Intellectual Property (Section 9).
If any provision of these Terms is found to be unenforceable or invalid, the remaining provisions shall remain in full force and effect.
These Terms of Use, together with the Privacy Policy, constitute the entire agreement between you and the developer regarding the use of NightCurve, superseding any prior agreements.
We reserve the right to modify these Terms of Use at any time. Material changes will be communicated through the app. Continued use of the app after changes constitutes acceptance of the new terms.