Health Calculators Comparison
All 68 Health calculators in one comparison table, with the formula and a worked example for each.
What you can work out with these calculators
Health calculators turn measurements you already have — height, weight, age, activity — into the standard clinical estimates: BMI, resting metabolic rate, body fat and heart-rate zones. They are screening and planning tools, not diagnoses, and the assumptions behind each formula are stated so you can judge how well it fits you.
- Check BMI and see how it sits against the published healthy range for your height.
- Estimate daily calorie needs from BMR plus an activity multiplier, rather than a fixed guess.
- Estimate body-fat percentage from tape measurements using the Navy method.
- Convert a target weekly weight change into a realistic daily calorie adjustment.
Compare calculators by what you enter
All 68 calculators here, one row each: what each tool works out and the fields it asks for before it does. Open any row to use the calculator itself.
| Calculator | What it works out | What you enter |
|---|---|---|
| BMI Calculator | Calculate Body Mass Index with category | Weight (kg) · Height (cm) |
| BMR Calculator | Basal metabolic rate — 3 formulas: Mifflin-St Jeor, Harris-Benedict, Katch-McArdle | Formula · Weight (kg) · Height (cm) · Age · Gender |
| Calorie Calculator | Daily calorie needs (TDEE) | BMR Formula · Weight (kg) · Height (cm) · Age · Gender |
| Body Fat Calculator | Estimate body fat percentage (Navy method) | Weight (kg) · Waist (cm) · Neck (cm) · Height (cm) · Gender |
| Water Intake Calculator | Daily water requirement | Weight (kg) · Activity (min/day) |
| Ideal Weight Calculator | Calculate ideal body weight (Devine) | Height (cm) · Gender |
| Heart Rate Zone Calculator | Target heart rate zones for exercise | Age |
| Pregnancy Due Date | Calculate pregnancy due date | Last Menstrual Period |
| Ovulation Calculator | Calculate ovulation date | Last Period Date · Cycle Length (days) |
| Macronutrient Calculator | Calculate daily macros (protein/carbs/fat) | Daily Calories · Protein (%) · Carbs (%) · Fat (%) |
| Lean Body Mass | Calculate lean body mass | Weight (kg) · Body Fat (%) |
| Body Surface Area | Calculate body surface area (Mosteller) | Weight (kg) · Height (cm) |
| Waist-to-Hip Ratio | Calculate WHR and health risk | Waist (cm) · Hip (cm) |
| VO2 Max Calculator | Estimate cardiovascular fitness | 1.5 Mile Run (min) · Age · Gender |
| Pregnancy Weight Gain | Recommended pregnancy weight gain | Pre-pregnancy BMI · Trimester |
| Blood Pressure Category | Check blood pressure category | Systolic · Diastolic |
| Calorie Burn Calculator | Calories burned by activity | Weight (kg) · Activity (MET) · Duration (min) |
| Sleep Calculator | Calculate optimal sleep times | Wake Up Time |
| GFR Calculator | Estimate kidney function | Serum Creatinine (mg/dL) · Age · Gender |
| Target Heart Rate Zones | Calculate your heart rate training zones | Age · Resting Heart Rate (bpm) · Training Intensity |
| Sleep Quality Score | Calculate your sleep quality score based on duration and efficiency | Hours in Bed · Hours Asleep · Night Wakings |
| Fatigue Score Calculator | Calculate your fatigue level based on sleep, activity, and stress | Avg Sleep Last 3 Days (hours) · Physical Activity (1-10) · Stress Level (1-10) |
| Navy Body Fat Calculator | Body fat % using the US Navy tape method | Gender · Waist (inches) · Neck (inches) · Height (inches) |
| Calorie Deficit Calculator | Weight loss from a daily calorie deficit | Daily Deficit (kcal) · Duration (weeks) |
| Heart Rate Zones | Training zones from max heart rate | Age · Resting HR (bpm) |
| Ideal Body Weight | Ideal weight from multiple formulas | Gender · Height (cm) |
| Fasting Timer Calculator | Intermittent fasting windows and stages | Protocol · Last Meal Hour |
| Sleep Debt Calculator | Accumulated sleep deficit and recovery | Hours Needed/Night · Avg Hours Slept · Number of Days |
| MET Value / Calories Burned | Calories burned from MET value | MET Value · Body Weight (kg) · Duration (minutes) |
| Body Type Calculator | Ectomorph/Mesomorph/Endomorph estimate | Height (cm) · Wrist Circumference (cm) · Shoulder Width (cm) · Hip Width (cm) |
| Iron Intake Calculator | Daily iron needs by age and gender | Gender · Age · Pregnant/Lactating |
| Vitamin D Dosage | Supplementation estimate to raise vitamin D level | Current Level (ng/mL) · Target Level (ng/mL) |
| Calorie Surplus/Deficit Goal | Daily calorie target for gain or loss | TDEE (kcal/day) · Goal · Weeks |
| Burn Severity Calculator | Classify burns with the rule of nines (TBSA) | Head (%) · Torso (%) · Left Arm (%) · Right Arm (%) · Left Leg (%) |
| Drug Dosage Calculator | Weight-based medication dosage | Patient Weight (kg) · Dose per kg (mg/kg) · Times per Day |
| Pregnancy Trimester Calculator | Trimester and due date from last menstrual period | Last Menstrual Period (date) · As of Date (optional — default today) |
| Ovulation & Fertile Window | Estimate ovulation day and fertile window from cycle length | Cycle Length (days) · Luteal Phase (days) · Last Period Start (date) |
| Cholesterol Ratio & LDL | TC/HDL ratio, non-HDL and Friedewald LDL from a lipid panel | Total Cholesterol (mg/dL) · HDL (mg/dL) · Triglycerides (mg/dL) |
| Nap Planner & Sleep Cycles | Best nap times aligned to 90-minute sleep cycles | Wake Time (hour 0-23) · Wake Time (minutes) · Nap Length (min) |
| MAF Heart Rate (Aerobic Base) | Phil Maffetone 180-formula max aerobic heart rate | Age · Adjustment |
| Health Insurance Cost Share | Deductible, coinsurance and out-of-pocket max | Annual Deductible ($) · Coinsurance You Pay (%) · Out-of-Pocket Maximum ($) · Covered Charges This Year ($) |
| HbA1c to eAG Converter | Estimated average glucose from HbA1c percentage | HbA1c (%) |
| Glycemic Load Calculator | GL from glycemic index and carbs per serving | Glycemic Index (0-100) · Carbs per Serving (g) |
| Waist-to-Height Ratio Calculator | WHtR — a simple central obesity indicator | Waist (cm) · Height (cm) |
| Mean Arterial Pressure Calculator | MAP from systolic and diastolic blood pressure | Systolic (mmHg) · Diastolic (mmHg) |
| LDL Cholesterol Calculator | Friedewald LDL from total, HDL and triglycerides | Total Cholesterol (mg/dL) · HDL (mg/dL) · Triglycerides (mg/dL) |
| IV Drip Rate Calculator | Drops per minute for IV infusions | Volume (mL) · Time (hours) · Drop Factor (gtt/mL) |
| Creatinine Clearance Calculator | Cockcroft-Gault estimate of kidney filtration | Age (years) · Weight (kg) · Serum Creatinine (mg/dL) · Sex |
| Anion Gap Calculator | Metabolic acidosis screening from serum electrolytes | Sodium Na⁺ (mEq/L) · Chloride Cl⁻ (mEq/L) · Bicarbonate HCO₃⁻ (mEq/L) · Albumin (g/dL, optional) |
| QTc Calculator (Bazett) | Heart-rate corrected QT interval from an ECG | Measured QT (ms) · Heart Rate (bpm) |
| Ponderal Index Calculator | Height-normalised body mass — fairer than BMI at height extremes | Weight (kg) · Height (m) |
| Mifflin-St Jeor BMR Calculator | Basal metabolic rate by the current standard equation | Weight (kg) · Height (cm) · Age (years) · Sex (1=male, 0=female) |
| TDEE and Macro Calculator | Daily calorie burn plus protein, carb, and fat targets | Weight (kg) · Height (cm) · Age · Sex (1=male, 0=female) · Activity Multiplier (1.2–1.9) |
| eGFR Calculator (CKD-EPI 2021) | Kidney filtration rate from creatinine, age, and sex | Serum Creatinine (mg/dL) · Age (years) · Sex (1=female, 0=male) |
| Adjusted Body Weight Calculator | Amputee-adjusted weight using percent of limb loss | Measured Weight (kg) · Amputation (% of body weight) |
| Glasgow Coma Scale Calculator | Eye, verbal, and motor response scoring | Eye response (1-4) · Verbal response (1-5) · Motor response (1-6) |
| APGAR Score Calculator | Newborn condition at 1 and 5 minutes after birth | Appearance/color (0-2) · Pulse (0-2) · Grimace/reflex (0-2) · Activity/tone (0-2) · Respiration (0-2) |
| Vaccination Due Calculator | Routine CDC child vaccines due at a given age | Child Age (months) |
| Pediatric Dose Calculator | Weight-based mg dose with a per-kg rate | Child Weight (kg) · Dose Rate (mg/kg) · Adult Maximum Dose (mg) |
| Corrected Calcium Calculator | Calcium level adjusted for low albumin (Payne formula) | Measured Calcium (mg/dL) · Albumin (g/dL) |
| Winter's Formula Calculator | Expected respiratory compensation for metabolic acidosis | Bicarbonate (mEq/L) |
| Maintenance Fluids Calculator (4-2-1) | Hourly pediatric maintenance fluid rate by the 4-2-1 rule | Weight (kg) |
| Free Water Deficit Calculator | Water deficit in hypernatremia from serum sodium and weight | Serum Sodium (mEq/L) · Weight (kg) |
| Serum Osmolality Calculator | Calculated plasma osmolality from sodium, glucose, and BUN | Sodium (mEq/L) · Glucose (mg/dL) · BUN (mg/dL) |
| Total Body Water Calculator | Body water estimate via the Watson formula | Weight (kg) · Height (cm) · Age (years) · Sex |
| P/F Ratio Calculator | PaO₂/FiO₂ ratio for oxygenation assessment | PaO₂ (mmHg) · FiO₂ (%) |
| Pet Medication Dosage Calculator | Free pet medicine dose calculator: converts a weight-based mg per kg dose into the millilitres to draw, for common vet-prescribed drugs. | Pet weight (kg) · Medication |
| Peptide Reconstitution Calculator | Calculate peptide concentration from vial amount and reconstitution volume, then the volume and syringe units for an amount per dose | Vial amount (mg) · Reconstitution volume (mL) · Amount per dose (µg) · Syringe scale |
Prefer the annotated list? Browse the full list with one line on what each calculator does.
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