Health & Body
6 free health tools — no sign-up required
Free tools for BMI, daily calorie needs, body fat percentage, ideal weight, water intake, sleep cycles, and more.
BMI Calculator
Calculate your Body Mass Index from height and weight
Calorie Calculator
Daily calorie needs via Mifflin-St Jeor equation
Sleep Cycle Calculator
Explore timing with assumed 90-minute sleep intervals
Body Fat
Estimate body fat percentage using the US Navy Method
Ideal Weight
Find your ideal weight range using the Devine Formula
Water Intake
Personalized daily hydration goals by weight and activity
About These Health & Body Calculators
BMI is an adult height-to-weight screening ratio. Calorie estimates use Mifflin–St Jeor and an assumed activity factor. Body Fat uses tape measurements and the Navy circumference equation. These outputs are different measurements; a healthy-looking value in one does not diagnose your overall health.
Ideal Weight compares historical height-based formulas rather than prescribing a target. Water Intake uses a rough weight and activity rule, and Sleep Cycle illustrates fixed 90-minute timing intervals. Neither is a personalized clinical recommendation. Pregnancy, adolescence, fluid restrictions and persistent symptoms need individual advice.
What Makes These Tools Stand Out
Compare consistent assumptions
Change one input at a time, keep track of the units and compare both the result and the exclusions stated on each tool.
Check the worked example
Each tool includes a specific example, its calculation method and reference links. Use these to understand the result before applying it to your own situation.
Frequently Asked Questions
Where should I start?
BMI is an adult height-to-weight screening ratio. Calorie estimates use Mifflin–St Jeor and an assumed activity factor. Body Fat uses tape measurements and the Navy circumference equation. These outputs are different measurements; a healthy-looking value in one does not diagnose your overall health.
Can I rely on the result for an important decision?
Results depend on your inputs and the model's limitations. They are not financial advice, not medical advice and not legal advice or tax advice. Verify consequential results with an appropriate professional.
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