Health tools
Health calculators
BMI, calories, macros, hydration, sleep and recovery — informational health helpers, not medical advice.
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PopularBMI Calculator
Body mass index, with range meter.
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Calorie Calculator
Daily calorie target (TDEE).
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Macro Calculator
Protein, carbs, fat split.
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Body Fat Calculator
Estimate body-fat % (Navy method).
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Water Intake Calculator
How much water you need daily.
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BMR Calculator
Calories your body burns at rest.
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TDEE Calculator
Daily maintenance calories from activity.
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Lean Body Mass Calculator
Estimate lean mass and fat mass.
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Waist-to-Height Ratio Calculator
Simple body-shape ratio.
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Sleep Need Calculator
Bedtime from your wake time.
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Sleep Debt Calculator
Missed sleep over recent days.
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Heart Rate Zones Calculator
Training intensity zones from age.
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Caffeine Cutoff Calculator
When to stop caffeine before bed.
Most used in Health
Common tasks
- Estimate BMI in metric or imperial
- Find a daily calorie target (TDEE)
- Split daily calories into protein/carbs/fat
- Estimate body-fat percentage from measurements
- Set a daily water intake goal
- Estimate BMR and maintenance calories
- Plan a sensible bedtime and track sleep debt
- See training heart-rate zones by age
Body estimates
Energy needs
Sleep & recovery
Fitness intensity
Frequently asked
Are these calculators medical advice?
No. They're informational estimates. Talk to a qualified healthcare professional for personal recommendations.
Why does BMI not work for athletes?
BMI is a height-and-weight ratio. Muscular bodies often score 'overweight' even when body fat is low.
Which method does Body Fat use?
The US Navy circumference method, with metric or imperial measurements for neck, waist and (for women) hip.
How precise are the calorie numbers?
TDEE is an estimate based on Mifflin-St Jeor BMR and an activity multiplier. Use it as a starting point and adjust based on results.
How accurate are the heart-rate zones?
Max HR uses the Tanaka formula (208 − 0.7 × age). It's a population estimate — your true max can vary by 10–20 bpm.