Health & Fitness
Quick health calculators for everyday questions: is my weight in a healthy range, how many calories do I burn, how much water should I drink, when should I go to bed to wake up refreshed, when is the baby due. Each tool uses widely published formulas and explains what the numbers mean. They are educational estimates and not a substitute for advice from a doctor or dietitian.
6 free tools. Tap any card to open it. No sign-up needed.
Choosing the right health calculator
- Weight range: the BMI calculator gives a quick screening category; the body fat calculator adds a circumference-based estimate.
- Food and energy: the calorie calculator estimates daily energy needs (TDEE) from your size and activity level.
- Hydration: the water intake calculator gives a starting target that you can adjust for heat and exercise.
- Pregnancy: the due date calculator estimates the date from the first day of your last period.
Use the numbers wisely
Every tool here uses a published formula and explains its limits. Measure the same way each time and watch the trend over several weeks rather than one reading. Results are general estimates, not medical advice. If you are pregnant, have a health condition or take medication, talk to a doctor or registered dietitian before changing your diet or exercise. Our health guides explain each formula and link to the official sources.
Guides and articles
- How Much Water Should I Drink a Day? What the Guidelines SayWhat official guidelines say about daily water intake, why the 8-glasses rule is only a rough guide, and how body weight, exercise and heat change your needs.
- How Many Calories Should I Eat to Lose Weight?Estimate how many calories you need to lose weight safely: work out maintenance calories (TDEE), choose a moderate deficit and adjust using real results.
- How to Measure Body Fat at Home With a Tape MeasureMeasure your body fat percentage at home with a tape measure and the U.S. Navy method: where to measure, worked examples, accuracy and other methods compared.
- Date Calculations: Days Between Dates and AgeHow to count days between dates, calculate exact age, handle leap years and business days, and convert times across zones.
- Calories, BMR and TDEE: How Many Calories Do You Need?Understand basal metabolic rate, total daily energy expenditure, activity multipliers and how to set a realistic calorie target.
- BMI Explained: What It Tells You and What It Doesn’tHow body mass index is calculated, what the categories mean, where BMI falls short, and better measures to use alongside it.
