Daily Health Toolkit
32+ free, evidence-based health calculators with peer-reviewed formulas
Every calculator uses peer-reviewed medical equations and runs entirely in your browser. Your health data never leaves your device. See our Methodology & Sources.
Understand Your Body With Evidence-Based Health Calculators
Daily Health Toolkit gives you free access to the same clinically validated formulas used by healthcare professionals, dietitians, and fitness trainers. Whether you want to check your BMI, understand your calorie needs, or optimize your daily hydration, every tool here is built on established medical research — not guesswork.
Our calculators are designed around the principle that better health decisions start with better information. Instead of relying on generic "one-size-fits-all" advice like "eight glasses a day," our tools personalize each result to your weight, height, age, gender, and activity level.
Why You Can Trust Our Numbers
Each calculator on this site is powered by formulas published in peer-reviewed journals and adopted by major health organizations:
- BMI uses the World Health Organization classification standard, the most widely used screening metric in medicine.
- BMR and calorie needs use the Mifflin-St Jeor equation (1990), which research shows is the most accurate BMR formula for the general population.
- Heart rate zones use the Karvonen formula, the standard method for setting training intensity.
- Body fat estimates use the U.S. Navy circumference method, validated to within 3-4% of DEXA scans.
- Ideal weight averages four validated formulas (Hamwi, Devine, Robinson, Miller) to balance their individual limitations.
Full formulas, citations, and source links are documented on our Methodology page.
📈 Most Popular
BMI Calculator
Check your Body Mass Index instantly. See if you're underweight, normal, overweight, or obese.
Calculate →BMR Calculator
Find your Basal Metabolic Rate using the Mifflin-St Jeor equation. Know how many calories you burn at rest.
Calculate →TDEE Calculator
Total Daily Energy Expenditure — the number of calories you burn per day including all activity.
Calculate →Calorie Deficit Calculator
Plan your weight loss with a personalized calorie deficit. See projected timelines and milestones.
Calculate →Water Intake Calculator
How much water should you drink daily? Calculate your personalized hydration goal.
Calculate →Macro Calculator
Get your personalized protein, carbs, and fat targets based on your goals.
Calculate →💪 Body Composition
Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy method.
Calculate →Ideal Weight Calculator
Find your ideal weight range using 4 validated formulas (Hamwi, Devine, Robinson, Miller).
Calculate →Lean Body Mass
Calculate your lean body mass and fat mass using the Boer formula.
Calculate →Body Surface Area
BSA calculation using Mosteller and DuBois formulas.
Calculate →Body Type Calculator
Discover your body shape classification.
Calculate →Body Frame Size
Determine small, medium, or large frame using wrist measurement.
Calculate →Army Body Fat Calculator
U.S. Army body fat standards with pass/fail assessment.
Calculate →Ideal Body Fat %
Age-adjusted ideal body fat percentage ranges.
Calculate →Waist-to-Hip Ratio
WHR assessment with cardiovascular risk categories.
Calculate →🍴 Nutrition & Diet
Protein Calculator
Daily protein needs based on activity level and goals.
Calculate →Keto Calculator
Ketogenic diet macros: 70% fat, 25% protein, 5% carbs.
Calculate →Intermittent Fasting
Plan your eating and fasting windows (16:8, 18:6, 20:4).
Calculate →Calories Burned
How many calories do you burn during exercise? MET-based calculation.
Calculate →Weight Loss Calculator
Project your weight loss timeline with milestones.
Calculate →🏃 Fitness & Cardio
Heart Rate Zones
5 training zones using the Karvonen formula.
Calculate →Target Heart Rate
Finding your optimal training heart rate range.
Calculate →VO2 Max Calculator
Estimate your cardiovascular fitness level.
Calculate →Running Pace Calculator
Calculate pace, speed, and marathon finish estimates.
Calculate →Metabolic Age
Compare your metabolism to average for your age.
Calculate →🩹 Health Assessment
Blood Pressure
AHA blood pressure categories with recommendations.
Calculate →Cholesterol Ratio
Total/HDL and triglyceride/HDL ratio assessment.
Calculate →Diabetes Risk
Score-based type 2 diabetes risk assessment.
Calculate →Blood Alcohol Calculator
BAC estimation using the Widmark formula.
Calculate →Sleep Cycle Calculator
Find your ideal bedtime based on 90-minute sleep cycles.
Calculate →👶 Women's Health
🔧 Tools & Tracking
Progress Tracker
Log weight, track streaks, set goals, and visualize your journey with charts.
Start Tracking →Embeddable Widget
Add a free BMI calculator to any website with one line of code.
Get the Code →Methodology & Sources
Every formula cited with peer-reviewed sources. See how each calculator works.
Read More →How to Get the Most From Your Results
Numbers are only useful when you understand what to do with them. Here is a simple framework for turning your results into action:
1. Start with the basics
Begin with BMI, BMR & calorie needs, and water intake. These three give you a baseline snapshot of your weight status, daily energy needs, and hydration — the foundations of everyday health.
2. Go deeper with body composition
BMI alone can't distinguish muscle from fat. Use the body fat calculator (U.S. Navy method) and ideal weight calculator to get a fuller picture of your body composition and a target range that makes sense for your frame.
3. Build a plan with nutrition and fitness tools
Once you know your calorie target, use the macro calculator to split it into protein, carbs, and fat, and the calorie deficit calculator to project your weight-loss timeline. For training, the heart rate zone calculator and running pace calculator help you train at the right intensity.
4. Track over time
Health is a journey, not a snapshot. Use the progress tracker to log your weight and measurements, revisit your numbers every few weeks, and adjust your plan as your body changes.