Track your Blood Alcohol Content in real-time. Make smarter decisions with personalized BAC calculations, Siri voice commands, and safety features built right in.
Know Limit goes beyond basic BAC calculators with deep Apple ecosystem integration and real safety features.
Calculates your Blood Alcohol Content using the Widmark formula, personalized to your weight, gender, and metabolism.
"Hey Siri, what's my BAC?" Log drinks, check your status, and get sobriety predictions completely hands-free.
A full companion app on your wrist. Log drinks, check your BAC, and get complications right on your watch face.
Your BAC readings and water intake sync automatically to Apple Health, giving you a complete picture in one place.
See your current BAC right on your Lock Screen and Dynamic Island. Always know where you stand without opening the app.
SOS emergency contacts, one-tap Uber and Lyft integration, and location sharing keep you and your friends safe.
Set up your profile once and start tracking in seconds.
Tap to add a beer, wine, shot, or mixed drink. Choose from presets or customize the ABV and volume.
Watch your estimated Blood Alcohol Content update in real-time based on your personal profile and metabolism.
Get notified when you hit legal limits, see when you'll be sober, and call a ride with one tap if needed.
Know Limit integrates deeply with the Apple ecosystem for a seamless experience.
Last updated: February 23, 2026
Know Limit ("the App"), developed and operated by Onyx Security Services Inc., is committed to protecting your privacy. This Privacy Policy explains how we collect, use, and safeguard your information when you use our mobile application.
Know Limit stores the following data locally on your device:
This data is stored entirely on your device and is not transmitted to our servers.
With your explicit permission, Know Limit may read and write data to Apple Health, including:
HealthKit data is handled in strict accordance with Apple's HealthKit guidelines. We do not access HealthKit data for advertising or marketing purposes, and this data is never shared with third parties.
Know Limit requests location access only to enable safety features:
Your location is never stored, tracked, or shared beyond these specific use cases.
If you choose to attach images to your drink entries, the App may request access to your camera or photo library. These images are stored locally on your device only.
Know Limit uses the following third-party services:
All personal data is stored locally on your device. You can delete your data at any time by:
Know Limit is not intended for use by anyone under the legal drinking age in their jurisdiction. We do not knowingly collect information from minors.
We may update this Privacy Policy from time to time. Changes will be reflected on this page with an updated revision date.
If you have questions about this Privacy Policy, please contact us:
Onyx Security Services Inc.
15431 Sableton Crest Ln
Cypress, TX 77429
Phone: (346) 448-1243
Email: support@knowlimit.app
We're here to help you get the most out of Know Limit.
Know Limit uses the scientifically validated Widmark formula, accounting for your weight, gender, and metabolism. While it provides a reliable estimate, it should be used as a guide only. Individual BAC can vary based on food intake, hydration, medications, and other factors. When in doubt, don't drive.
Yes. Know Limit includes a full Apple Watch companion app. You can log drinks, check your BAC, and view sobriety predictions directly from your wrist. It also supports watch face complications for at-a-glance BAC monitoring.
Know Limit supports five Siri Shortcuts: "Log a beer in KnowLimit," "What's my BAC?", "Am I safe to drive?", "Log water in KnowLimit," and "When will I be sober?" You can customize these phrases in the Shortcuts app.
No. All your drink logs and personal data are stored locally on your device. The only third-party service used is Google AdMob for ads, which can be removed with a one-time $0.99 purchase. HealthKit data is never shared with third parties.
You can remove all advertisements with a one-time in-app purchase of $0.99. Go to your Profile/Settings within the app and tap "Remove Ads."
Have a question or issue? Reach out and we'll get back to you as soon as possible.
Want to see a specific drink or cocktail in the app? Let us know and we'll consider adding it.