Last updated: September 24, 2026
Calculation model
CaffCutoff applies a standard exponential half-life model to each logged dose, then adds the estimated remainders. For a dose D, elapsed time t, and half-life h, the model is D x (1/2)^(t/h). The default half-life is five hours, used as a practical midpoint rather than as a measurement of any person, with optional fast and slow presets spanning the commonly reported range.
The 25 mg bedtime target and 5 mg clearance target are product planning values created for this calculator. They are not clinical thresholds, exposure limits, or medical recommendations.
Public reference material
- Institute of Medicine: Pharmacology of Caffeine provides background on caffeine absorption, elimination, and the wide variation in half-life between people.
- U.S. Food and Drug Administration: Spilling the Beans explains that caffeine content and individual sensitivity vary. Its 400 mg discussion concerns most healthy adults and is not a personal limit for every user.
- USDA FoodData Central is a public reference for representative food and beverage nutrient data, including caffeine values.
These links are provided for transparency. The referenced organizations do not sponsor, endorse, or verify CaffCutoff.
Drink presets
Presets use rounded, representative values for generic drink categories. They are not claims about a particular brand or product. Formulation, preparation, serving size, and batch can change the actual amount, so a product label or manufacturer disclosure should take priority.
Content and visual assets
The site-specific written copy, interface layouts, logo, favicon, and social sharing graphic were created for CaffCutoff. The site does not use beverage-company logos or claim affiliation with a manufacturer, healthcare provider, or referenced organization.
Third-party software
CaffCutoff is built with open-source software, including Astro, React, Radix UI, and Lucide. Their copyright notices and license terms are available in the third-party notices.