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Free Health & Fitness Calculators

Use health and fitness calculators for quick educational estimates about body measurements, nutrition, pace, pregnancy dates, and wellness planning. The results are helpful for learning and planning, but they are not a diagnosis or a replacement for a qualified professional.

Use health estimates carefully

These calculators are best for learning ranges, comparing inputs, and planning questions to ask a professional. Results depend heavily on age, body, activity, history, and local guidance.

I want a basic body-size estimate Calculate BMI and read what the category can and cannot tell you. I am estimating calories Compare daily calorie needs from age, size, activity, and goal assumptions. I am checking pregnancy dates Estimate due dates from last period, conception, IVF, or ultrasound date. I need a kidney estimate explained Use eGFR education carefully and confirm medical meaning with a clinician.
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Guides that explain the limits

Health estimates need plain limits because a result can be useful and still not be medical advice. These guides explain what the number can and cannot tell you.

Priority guides

BMI guide Height, weight, category meaning, adult screening limits, and when BMI is not enough. Calorie guide Age, height, weight, activity, goal settings, and why calorie estimates vary. Due date guide LMP, conception, IVF, ultrasound dates, and why clinicians may adjust the date. GFR guide Kidney estimate inputs, lab context, and why medical follow-up matters.

What this category helps with

  • Fitness, nutrition, pregnancy, kidney, alcohol, and body-measurement estimates with visible limits.
  • Educational calculators that explain inputs and formulas without turning estimates into diagnoses.
  • Guide links and source notes for topics where context matters.

Start with these tools

BMI Calculator Estimate adult body mass index and healthy BMI weight range. Underweight BMI Calculator Check adult BMI against the underweight screening threshold with careful safety notes. Overweight BMI Calculator Check adult BMI against overweight and obesity screening categories. Nutrition Points Calculator Create a transparent food-label score from calories, saturated fat, added sugar, sodium, fiber, and protein. Calorie Calculator Estimate daily calories from BMR, activity level, and goal. Body Fat Calculator Estimate body fat percentage with a Navy-style tape method.

All health and fitness calculators

Open a tool, try the examples, then use the matching guide when you need more explanation.

BMI Calculator Estimate adult body mass index and healthy BMI weight range. Open Underweight BMI Calculator Check adult BMI against the underweight screening threshold with careful safety notes. Open Overweight BMI Calculator Check adult BMI against overweight and obesity screening categories. Open Nutrition Points Calculator Create a transparent food-label score from calories, saturated fat, added sugar, sodium, fiber, and protein. Open Calorie Calculator Estimate daily calories from BMR, activity level, and goal. Open Body Fat Calculator Estimate body fat percentage with a Navy-style tape method. Open BMR Calculator Estimate resting calories with the Mifflin-St Jeor equation. Open Ideal Weight Calculator Estimate Devine ideal body weight and compare it with the adult healthy BMI range. Open Pace Calculator Calculate running, walking, or cycling pace and speed from time and distance. Open Army Body Fat Calculator Estimate Army one-site tape body fat from weight and abdomen circumference. Open Lean Body Mass Calculator Estimate Boer lean body mass from height, weight, and formula sex. Open Healthy Weight Calculator Find the adult BMI 18.5 to 24.9 weight range for a height. Open Calories Burned Calculator Estimate exercise calories from MET, body weight, and duration. Open One Rep Max Calculator Estimate one-rep max from weight lifted and reps completed. Open Target Heart Rate Calculator Estimate exercise heart-rate zones in beats per minute. Open Pregnancy Calculator Estimate due date, pregnancy week, conception timing, and trimester from LMP. Open Pregnancy Weight Gain Calculator Compare current pregnancy weight gain with BMI-based singleton ranges. Open Pregnancy Conception Calculator Estimate conception date, window, and LMP from a due date. Open Due Date Calculator Estimate pregnancy due date from LMP and cycle length. Open Ovulation Calculator Estimate ovulation date and fertile window from cycle details. Open Conception Calculator Estimate conception date and fertile window from cycle details. Open Period Calculator Predict upcoming period dates from cycle length and period length. Open Macro Calculator Split daily calories into protein, fat, and carbohydrate grams. Open Carbohydrate Calculator Calculate carbohydrate grams from calories and carb percentage. Open Protein Calculator Estimate protein grams per day from body weight and target factor. Open Fat Intake Calculator Calculate daily dietary fat grams from calories and fat percentage. Open TDEE Calculator Estimate daily maintenance calories from BMR and activity level. Open GFR Calculator Estimate adult eGFR from serum creatinine with the 2021 CKD-EPI race-free equation. Open Body Type Calculator Estimate a broad body-shape category from shoulder, bust, waist, and hip measurements. Open Body Surface Area Calculator Estimate adult body surface area with Mosteller and Du Bois formula results. Open BAC Calculator Estimate blood alcohol concentration with a Widmark-style formula. Open Height Calculator Estimate adult height from parent heights with a rough expected range. Open Sleep Calculator Find a bedtime or wake-up time from 90-minute sleep cycles and a fall-asleep buffer. Open

Guides for this category

Each guide uses its matching tool, with example numbers and plain limits.