About VitalTally
Free, science-based health calculators that run entirely in your browser. No account, no data collection, no guesswork.
What VitalTally Is
VitalTally is a collection of four free health calculators designed to give you evidence-based estimates for everyday wellness decisions — how much you should eat, what your BMI means, when to sleep to wake refreshed, and how much water you need based on your activity level.
Every calculator runs entirely in your browser using JavaScript. Your height, weight, age, and any other data you enter is never transmitted to or stored on any server. VitalTally has no user accounts, no data collection beyond standard anonymized analytics, and no subscription tiers.
⚕️ Medical disclaimer: VitalTally provides health calculators for informational and educational purposes only. Results are estimates and are not medical advice. Always consult a qualified healthcare professional before making changes to your diet, exercise, or lifestyle.
The Four Calculators
Calculate your Body Mass Index and understand what the result means — including its well-documented limitations for individuals with high muscle mass or different body compositions.
Estimate your TDEE (Total Daily Energy Expenditure) using the Mifflin-St Jeor equation, with targets for weight loss, maintenance, and muscle gain based on your activity level.
Find the optimal bedtime or wake time aligned with your natural sleep cycles (~90 min each), so you wake at the lightest sleep stage feeling refreshed rather than groggy.
Get a personalized daily water intake estimate based on your body weight and activity level, with context about how exercise, climate, and other factors affect your needs.
Our Approach to Health Information
VitalTally calculators are built on widely validated formulas used in clinical and research settings:
- BMI uses the standard WHO formula (weight ÷ height²) with the WHO adult classification thresholds, alongside context about its limitations
- Calories uses the Mifflin-St Jeor equation (1990), the most validated BMR formula for the general adult population, with standard activity multipliers
- Sleep uses the established 90-minute sleep cycle model from sleep science research, plus the National Sleep Foundation's age-based recommendations
- Hydration uses weight-based and activity-adjusted estimates consistent with National Academies of Sciences guidelines
Every calculator result is accompanied by explanatory content covering what the number means, its limitations, and when to seek professional guidance. We believe health information is most useful when you understand the context behind the numbers, not just the numbers themselves.
Who Uses VitalTally
- People tracking fitness goals — using calorie and BMI data to monitor progress alongside other health markers
- Those managing sleep schedules — aligning sleep timing with natural cycles to reduce morning grogginess
- Athletes and active individuals — calculating hydration needs adjusted for training load and climate
- Anyone wanting context — understanding what their BMI category actually means, including the limitations of BMI as a measure of individual health
Privacy and Data
Health data is among the most sensitive personal information there is. VitalTally is built so that we never have access to yours. All calculator logic runs as JavaScript on your device; nothing you enter is transmitted anywhere. We use Google Analytics for anonymized traffic measurement and Google AdSense for advertising — standard tools used by millions of websites. Neither provides us with your health data.
Full details are in our Privacy Policy.
Contact
Questions, corrections, or suggestions: Contact us. If a calculator is producing results that seem incorrect, or if you have a suggestion for improving the explanatory content, we want to hear it.