# HealthCalc.app > Free health, fitness, and nutrition calculators backed by peer-reviewed clinical formulas. Instant results with zero sign-up required. HealthCalc.app provides 33 specialized evidence-based calculators covering energy balance, body composition, athletic performance, medical screening, and diet protocols. Every tool supports both metric and imperial units, compares multiple peer-reviewed equations, and provides actionable interpretations. ## Calorie & Energy Calculators - [TDEE Calculator](https://healthcalc.app/tdee-calculator/): Calculate Total Daily Energy Expenditure using Mifflin-St Jeor, Harris-Benedict, Katch-McArdle, and Schofield formulas with activity and step multipliers. - [BMR Calculator](https://healthcalc.app/bmr-calculator/): Calculate Basal Metabolic Rate across 4 clinical formulas to determine baseline calorie burn at complete rest. - [RMR Calculator](https://healthcalc.app/rmr-calculator/): Calculate Resting Metabolic Rate comparing Cunningham, Owen, Mifflin-St Jeor, and Harris-Benedict equations with metabolic adaptation adjustments. - [Calorie Deficit Calculator](https://healthcalc.app/calorie-deficit-calculator/): Estimate daily caloric targets to lose 0.5 to 2 lbs per week with adaptive metabolic timelines and macro breakdowns. - [Macro Calculator](https://healthcalc.app/macro-calculator/): Calculate daily protein, carbohydrate, and fat targets for weight loss, maintenance, or muscle gain across 5 diet presets. ## Body Composition Calculators - [Body Fat Calculator](https://healthcalc.app/body-fat-calculator/): Estimate body fat percentage using US Navy circumference, Jackson-Pollock 3-site caliper, YMCA, and BMI methods. - [BMI Calculator](https://healthcalc.app/bmi-calculator/): Calculate Body Mass Index using standard Quetelet and Oxford New BMI formulas with CDC pediatric percentiles. - [FFMI Calculator](https://healthcalc.app/ffmi-calculator/): Calculate Fat-Free Mass Index (raw and height-adjusted) to assess natural muscular potential and drug-free physiological limits. - [Lean Body Mass Calculator](https://healthcalc.app/lean-body-mass-calculator/): Estimate lean muscle mass using Boer, James, Hume, and Katch-McArdle formulas. - [Ideal Weight Calculator](https://healthcalc.app/ideal-weight-calculator/): Calculate ideal body weight ranges using Robinson, Devine, Hamwi, Miller formulas, and WHO BMI boundaries. - [Waist-to-Hip Ratio Calculator](https://healthcalc.app/waist-to-hip-ratio-calculator/): Calculate WHR to assess cardiometabolic health risk, body shape classification, and golden ratio proportions. - [Waist-to-Height Ratio Calculator](https://healthcalc.app/waist-to-height-ratio-calculator/): Calculate WHtR with Ashwell health boundaries and US military body fat compliance standards. ## Nutrition & Macro Calculators - [PSMF Calculator](https://healthcalc.app/psmf-calculator/): Calculate daily Protein Sparing Modified Fast (PSMF) macros, Lyle McDonald Category 1/2/3 classification, refeed schedules, food equivalents, and mandatory electrolyte shield for rapid fat loss. - [Body Recomposition Calculator](https://healthcalc.app/body-recomposition-calculator/): Calculate daily calories and macros to build muscle and burn body fat simultaneously with training day vs rest day calorie cycling and a 12-week body transformation projection. - [Keto Macro Calculator](https://healthcalc.app/keto-calculator/): Calculate personalized daily net carbs limits, lean body mass protein goals, fat satiety levers, and daily electrolyte protocols for ketosis. - [Carnivore Diet Calculator](https://healthcalc.app/carnivore-diet-calculator/): Calculate carnivore diet macros and meat portions (ribeye, ground beef, eggs, butter) across 80:20, 70:30, and 60:40 fat:protein ratios. - [Cutting Calculator](https://healthcalc.app/cutting-calculator/): Calculate bodybuilding cutting calories and macros with Alpert muscle-catabolism safeguards and 5:2 carb refeed protocols. - [Reverse Diet Calculator](https://healthcalc.app/reverse-diet-calculator/): Generate week-by-week caloric increases to restore metabolic rate post-diet while minimizing fat regain. - [Carb Cycling Calculator](https://healthcalc.app/carb-cycling-calculator/): Calculate custom high, moderate, low, and zero-carb day macros aligned with workout schedules. - [Intermittent Fasting Calculator](https://healthcalc.app/intermittent-fasting-calculator/): Plan 16:8, 18:6, 20:4, and OMAD fasting and eating windows with sleep overlap analysis. - [Ramadan Fasting Calculator](https://healthcalc.app/ramadan-fasting-calculator/): Calculate adjusted TDEE, Suhoor, and Iftar macro and hydration distributions during holy fasting hours. ## Fitness & Performance Calculators - [One Rep Max Calculator](https://healthcalc.app/one-rep-max-calculator/): Calculate 1RM for bench, squat, and deadlift using Brzycki, Epley, Lander, Lombardi, and O'Conner formulas with RPE and plate loading. - [VO2 Max Calculator](https://healthcalc.app/vo2-max-calculator/): Estimate maximal oxygen uptake without wearables using Cooper 12-min, Rockport 1-mile walk, George jog, or non-exercise algorithms. - [Grip Strength Calculator](https://healthcalc.app/grip-strength-calculator/): Compare dynamometer readings against Mathiowetz clinical norms and EWGSOP2 sarcopenia diagnostic cut-offs. - [Zone 2 Heart Rate Calculator](https://healthcalc.app/zone-2-heart-rate-calculator/): Calculate aerobic endurance and fat oxidation training zones using Tanaka, Gellish, and Karvonen heart rate reserve methods. ## Health & Medical Calculators - [Blood Pressure Calculator](https://healthcalc.app/blood-pressure-calculator/): Classify blood pressure readings under AHA/ACC guidelines, Mean Arterial Pressure (MAP), pulse pressure, and age-specific cardiovascular percentiles. - [Biological Age Calculator](https://healthcalc.app/biological-age-calculator/): Estimate biological body age using 15 lifestyle biomarkers and optional Levine PhenoAge blood test metrics. - [HRV Calculator](https://healthcalc.app/hrv-calculator/): Analyze Heart Rate Variability (rMSSD / SDNN) against population age percentiles to assess autonomic recovery and stress. - [Sleep Calculator](https://healthcalc.app/sleep-calculator/): Calculate optimal bedtimes and wake-up times based on 90-minute sleep cycles and individual sleep latency. ## Pregnancy & Family Calculators - [Pregnancy Due Date Calculator](https://healthcalc.app/pregnancy-due-date-calculator/): Calculate estimated due date, gestational age, and trimester by LMP, conception, IVF transfer, or ultrasound. - [Ovulation Calculator](https://healthcalc.app/ovulation-calculator/): Predict fertile windows, ovulation dates, and conception probability using cycle history, BBT, and LH markers. - [Pediatric Growth Calculator](https://healthcalc.app/pediatric-growth-calculator/): Track infant and child height, weight, head circumference, and BMI against WHO (0-2 yrs) and CDC (2-20 yrs) growth charts. ## Nutrition & Hydration Calculators - [Protein Calculator](https://healthcalc.app/protein-calculator/): Calculate optimal daily protein intake for general health, hypertrophy, fat loss, and GLP-1 medication support. - [Water Intake Calculator](https://healthcalc.app/water-intake-calculator/): Calculate baseline daily fluid requirements adjusted for exercise intensity and climate with an 8-hour schedule. - [Water Weight Cut Calculator](https://healthcalc.app/water-weight-cut-calculator/): Plan fight-week water loading, sodium manipulation, gut cut, and rehydration for MMA and wrestling weigh-ins. ## Optional - [Full Calculator & Scientific Formula Reference](https://healthcalc.app/llms-full.txt): Comprehensive technical documentation with exact mathematical equations, input parameter types, output schema structures, and clinical citations for all 33 calculators.