Health & fitness
Explore health calculators and learn badminton, tennis, table tennis and pickleball with interactive rules diagrams. Estimate BMI, waist ratio, calories and nutrition servings with clear limits.
Badminton Rules: Interactive Guide
Compare court boundaries, practice doubles service turns and try 21-point or new 15-point scoring with diagrams and an eight-question quiz.
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Tennis Rules: Interactive Guide
Learn serves, volleys, doubles order and line calls with court diagrams. Practice a game, a set or a tiebreak, then try an eight-question quiz.
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Table Tennis Rules: Interactive Guide
Learn serving, two-point service turns, deuce, net lets, edge balls and doubles order with animated diagrams, a practice scoreboard and a six-question quiz.
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Pickleball Rules: Interactive Court Guide
Learn pickleball serving, the two-bounce rule, kitchen faults and doubles serve order with court animations, line-call examples and a five-question quiz.
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BMI Calculator
Calculate adult body mass index from height and weight locally in your browser.
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BMR Calculator
Estimate basal metabolic rate with the Mifflin-St Jeor formula locally in your browser.
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TDEE Calculator
Estimate total daily energy expenditure from BMR and activity level locally in your browser.
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Daily Calorie Goal Calculator
Estimate a daily calorie target for maintenance, fat loss, or weight gain locally in your browser.
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Waist-to-Height Ratio Calculator
Calculate adult waist-to-height ratio with metric or US customary units and compare it with the half-your-height screening guideline.
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Nutrition Label Serving Calculator
Calculate calories and nutrients for your portion using values from an existing food label. Choose per serving or per 100 g/mL, and compare your portion with the whole package.
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These calculators are useful starting estimates, not diagnoses or personalized treatment. Use the result to understand a formula, then compare it with longer-term measurements, habits, and professional guidance when needed.
- Use BMI for a quick height-to-weight screening value, not a direct body-fat measurement.
- Use BMR as the resting-energy estimate, then TDEE when normal daily activity also needs to be included.
- Treat a calorie goal as a starting range and review two to four weeks of weight, waist, food, and training records before adjusting it.
| Task | Start with | Why |
|---|---|---|
| Calculate adult body mass index | BMI Calculator | Uses height and weight for a common adult screening reference. |
| Estimate calories used at rest | BMR Calculator | Uses the Mifflin-St Jeor equation as a resting-energy estimate. |
| Estimate maintenance calories | TDEE Calculator | Adds an activity factor to the BMR estimate. |
| Plan a maintenance, loss, or gain target | Calorie Goal Calculator | Compares a selected goal with estimated TDEE. |
| Compare waist size with height | Waist-to-Height Ratio Calculator | Uses the same unit for waist and height and explains the half-height screening guideline. |
| Scale a Nutrition Facts serving | Nutrition Label Serving Calculator | Recalculates listed nutrients for the amount actually eaten. |