Health Tools
Practical Tools for Everyday Wellness
Three small utilities for planning a bedtime, checking how consistent your habits are, and estimating a daily fluid range. Each shows its math and its limits, and none of them is a medical test.
Circadian sleep window estimator
Enter when you need to wake up and how much sleep you are aiming for. The tool works backward to a lights-out time and handles schedules that cross midnight.
No duration is presented as right for everyone. Needs vary by age, health and the demands of your week.
Longevity Score Index
A summary of how consistent your everyday habits are against common benchmarks. It is a planning checklist, not a prediction.
How the score is built
- Movement: up to 25 points
- Sleep regularity: up to 20
- Dietary variety: up to 20
- Tobacco avoidance: up to 20
- Preventive follow-through: up to 15
Each answer earns a fixed share of its factor's points. The five contributions add up to a total out of 100.
It is not a biological age, life expectancy, disease risk or clinical longevity prediction, and a higher score does not guarantee a longer life.
Hydration planner
A rough planning range for fluids from drinks, based on body weight with adjustments for activity and heat.
The math: 30 mL per kilogram of body weight, plus 0, 350 or 700 mL for activity, plus 500 mL for hot weather or heavy sweating, shown as a range of plus or minus 10 percent.
People with fluid restrictions, or with heart, kidney or liver conditions, should follow guidance from their healthcare professional instead of this estimate.
How to read your results
Estimates are only as good as the inputs and the assumptions behind them. Keep these limits in mind.
They are averages
Formulas use general benchmarks. Your age, health, medications and circumstances can shift what is right for you.
Inputs are self-reported
Small changes in what you enter move the output. A different honest answer can give a different number.
They are not diagnoses
If something worries you, such as constant fatigue or unusual thirst, talk with a licensed healthcare professional.
Your inputs stay on your device
Everything you enter in these tools is processed locally in your browser and is not intentionally sent to a server. Nothing is saved in local storage, so values clear when you refresh or leave the page.
Want the reasoning behind the numbers?
The guides explain the research on sleep, hydration, activity and scores, including where the evidence runs out.