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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.
Browse and filter health & fitnessAll health and fitness calculators
Choose a tool for your task. Open its matching guide when you need the inputs or results explained.
BMI CalculatorEstimate adult body mass index and healthy BMI weight range.Underweight BMI CalculatorCheck adult BMI against the underweight screening threshold with careful safety notes.Overweight BMI CalculatorCheck adult BMI against overweight and obesity screening categories.Nutrition Points CalculatorCreate a transparent food-label score from calories, saturated fat, added sugar, sodium, fiber, and protein.Calorie CalculatorEstimate daily calories from BMR, activity level, and goal.Body Fat CalculatorEstimate body fat percentage with a Navy-style tape method.
Browse all 33 health & fitness
The 6 choices above and these 27 tools make up this category.
- BMR CalculatorEstimate resting calories with the Mifflin-St Jeor equation.
- Ideal Weight CalculatorEstimate Devine ideal body weight and compare it with the adult healthy BMI range.
- Pace CalculatorCalculate running, walking, or cycling pace and speed from time and distance.
- Army Body Fat CalculatorEstimate Army one-site tape body fat from weight and abdomen circumference.
- Lean Body Mass CalculatorEstimate Boer lean body mass from height, weight, and formula sex.
- Healthy Weight CalculatorFind the adult BMI 18.5 to 24.9 weight range for a height.
- Calories Burned CalculatorEstimate total and active exercise calories from MET, weight, and time.
- One Rep Max CalculatorEstimate one-rep max from weight lifted and reps completed.
- Target Heart Rate CalculatorEstimate target heart-rate zones by age or turn a timed pulse count into BPM.
- Pregnancy CalculatorEstimate due date, pregnancy week, conception timing, and trimester from LMP.
- Pregnancy Weight Gain CalculatorCompare current pregnancy weight gain with BMI-based singleton ranges.
- Pregnancy Conception CalculatorEstimate conception date, window, and LMP from a due date.
- Due Date CalculatorEstimate pregnancy due date from LMP and cycle length.
- Ovulation CalculatorEstimate ovulation date and fertile window from cycle details.
- Conception CalculatorEstimate conception date and fertile window from cycle details.
- Period CalculatorPredict upcoming period dates from cycle length and period length.
- Macro CalculatorSplit daily calories into protein, fat, and carbohydrate grams.
- Carbohydrate CalculatorCalculate carbohydrate grams from calories and carb percentage.
- Protein CalculatorEstimate protein grams per day from body weight and target factor.
- Fat Intake CalculatorCalculate daily dietary fat grams from calories and fat percentage.
- TDEE CalculatorEstimate daily maintenance calories from BMR and activity level.
- GFR CalculatorEstimate adult eGFR from serum creatinine with the 2021 CKD-EPI race-free equation.
- Body Type CalculatorEstimate a broad body-shape category from shoulder, bust, waist, and hip measurements.
- Body Surface Area CalculatorEstimate adult body surface area with Mosteller and Du Bois formula results.
- BAC CalculatorEstimate blood alcohol concentration with a Widmark-style formula.
- Height CalculatorEstimate adult height from parent heights with a rough expected range.
- Sleep CalculatorFind a bedtime or wake-up time from 90-minute sleep cycles and a fall-asleep buffer.
Help choosing a tool and checking its results
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 estimateCalculate BMI and read what the category can and cannot tell you.I am estimating caloriesCompare daily calorie needs from age, size, activity, and goal assumptions.I am checking pregnancy datesEstimate due dates from last period, conception, IVF, or ultrasound date.I need a kidney estimate explainedUse 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 guideHeight, weight, category meaning, adult screening limits, and when BMI is not enough.Calorie guideAge, height, weight, activity, goal settings, and why calorie estimates vary.Due date guideLMP, conception, IVF, ultrasound dates, and why clinicians may adjust the date.GFR guideKidney estimate inputs, lab context, and why medical follow-up matters.
Health estimate pages to keep visible
Use these links as quick paths to educational estimates with visible limits and professional-advice cautions.
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.
Guides for this category
Each guide uses its matching tool, with example numbers and plain limits.
- How to use the BMI CalculatorLearn what BMI needs, what the category means, and why adult BMI is only a screening estimate.
- How to use the Underweight BMI CalculatorLearn how to check adult BMI against the underweight threshold without treating BMI as an eating-disorder diagnosis.
- How to use the Overweight BMI CalculatorLearn how adult BMI is compared with the overweight screening range and why the result is not a full health judgment.
- How to use the Nutrition Points CalculatorLearn how to use a transparent food-label score without copying proprietary diet-program points.
- How to use the Calorie CalculatorLearn how maintenance calories are estimated from BMR, activity, and goal settings.
- How to use the Body Fat CalculatorLearn how the Navy-style tape method creates a body-fat estimate and how to measure more consistently.
Browse all 33 guides in this category
- BMR Calculator: Mifflin-St Jeor GuideLearn what basal metabolic rate means and why it is the base for calorie planning.
- How to use the Ideal Weight CalculatorLearn how the Devine ideal body weight formula differs from an adult healthy BMI range.
- How to use the Pace CalculatorLearn how to convert workout distance and time into pace per mile or kilometer and speed per hour.
- How to use the Army Body Fat CalculatorLearn how the current Army one-site tape estimate uses body weight, abdomen circumference, and age-group reference limits.
- How to use the Lean Body Mass CalculatorLearn how the Boer formula estimates lean body mass from height, weight, and formula sex.
- How to use the Healthy Weight CalculatorLearn how the healthy-weight range is built from adult BMI 18.5 to 24.9.
- How to Calculate Calories Burned With METsLearn the MET calorie formula, pounds conversion, and total-versus-active calorie difference.
- How to use the One Rep Max CalculatorLearn how rep sets estimate one-rep max without testing a true max.
- Target Heart Rate Zones and Pulse BPM GuideLearn how age becomes an exercise zone and how a timed pulse count becomes beats per minute.
- How to use the Pregnancy CalculatorLearn how LMP and cycle length estimate due date, pregnancy week, and trimester.
- How to use the Pregnancy Weight Gain CalculatorLearn how pre-pregnancy BMI connects to singleton pregnancy weight-gain guideline ranges.
- How to use the Pregnancy Conception CalculatorLearn how a due date can be counted backward to estimate conception date, window, and LMP.
- How to use the Due Date CalculatorLearn how LMP and cycle length estimate a pregnancy due date.
- How to use the Ovulation CalculatorLearn how cycle length and luteal phase estimate ovulation and fertile window.
- How to use the Conception CalculatorLearn how LMP, cycle length, and luteal phase estimate conception timing and fertile window.
- How to use the Period CalculatorLearn how last period date, cycle length, and period length predict upcoming dates.
- How to use the Macro CalculatorLearn how calorie targets turn into grams of protein, fat, and carbs.
- How to use the Carbohydrate CalculatorLearn how daily calories and carb percent become carbohydrate grams.
- How to use the Protein CalculatorLearn how body weight and grams-per-kilogram targets estimate daily protein.
- How to use the Fat Intake CalculatorLearn how calories and fat percentage become daily dietary fat grams, with AMDR context and food-quality limits.
- How to use the TDEE CalculatorLearn how BMR and activity level estimate maintenance calories, and how to avoid over-trusting a TDEE result.
- How to use the GFR CalculatorLearn how the GFR Calculator uses age, sex, and creatinine to estimate adult eGFR.
- How to use the Body Type CalculatorLearn how shoulder, bust, waist, and hip measurements estimate a broad body-shape label.
- How to use the Body Surface Area CalculatorLearn how height and weight estimate adult body surface area with Mosteller and Du Bois formulas.
- How to use the BAC CalculatorLearn how drink size, ABV, body weight, sex, and time affect a BAC estimate.
- Height Calculator GuideUse the Height Calculator guide to enter parent heights, read the mid-parental estimate, check the rough range, and know when growth charts matter.
- Sleep Calculator GuideUse the Sleep Calculator guide to count 90-minute cycles, add a fall-asleep buffer, compare bedtime options, and know when sleep quality matters more.