Health Calculators
Browse free calculators for metabolism, body composition, nutrition, training, and clinical education. Each tool is a standalone page with formulas, examples, and links to related metrics so you can plan calories, macros, and activity in one sitting.
Jump to popular tools, fitness and activity, or health and nutrition. Read the overview below for responsible use.
Timers & Tools
- Stopwatch — lap splits for runs and workouts.
- Countdown Timer — set minutes and seconds with sound alert.
- Interval Timer — HIIT work/rest rounds for training.
- Pomodoro Timer — focus and break sessions.
Popular Calculators
- BMI Calculator
- BMR Calculator
- TDEE Calculator
- Calorie Calculator
- Macro Calculator
- Body Fat Calculator
Related: pediatric BMI, calorie deficit, protein intake, Navy body fat—see links in the lists above and below.
Fitness Calculators
- Calories Burned — with PAL and TDEE for context.
- Heart Rate Zones — plus target heart rate and VO2 max estimate.
- Exercise Hydration — and daily water intake.
- Daily Step Goal — distance heuristics alongside calories burned.
- VO2 Max Estimator — aerobic fitness with heart-rate targets.
- Target Heart Rate — training intensity with zones.
- Activity Level (PAL) — feeds TDEE and BMR.
- Metabolism Age (illustrative) — compare to BMR.
- Sleep Calculator — recovery next to injury recovery planner.
- Injury Recovery Planner — educational outline; not a substitute for care.
- One-Rep Max Estimator — Epley formula with calories burned.
- Running Pace Calculator — pace and speed from distance and time.
- Resting Heart Rate — trends with heart rate zones.
Health Calculators
- Weight Loss Planner — with deficit and calorie target.
- Weight Gain Planner — and macros.
- Calorie Deficit Calculator — ties to TDEE.
- Zig-Zag Calories — weekly averaging vs steady targets.
- Energy Expenditure (TDEE) — same family as BMR.
- Ideal Weight Calculator — reference with BMI.
- Waist-to-Hip Ratio — and waist-to-height.
- Body Adiposity Index — with body fat.
- Body Frame Calculator — context for ideal weight.
- Body Surface Area — pharmacology education.
- Daily Water Intake — water deficit model.
- Fiber Intake — with glycemic load.
- Sodium Converter — label literacy.
- Vitamin D Units — IU ↔ micrograms.
- Caffeine Intake — planning alongside hydration.
- Glycemic Load — meal planning with carb intake.
- Intermittent Fasting Window — schedule vs meal splits.
- Meal Calorie Split — and calories per meal.
- Breastfeeding Calorie Add-On — on top of maintenance.
- eGFR Calculator (educational) — study only; not for self-diagnosis.
- Corrected QT (QTc) — ECG education.
- Cholesterol Ratio — lab context.
- Diabetes Risk Checklist — screening prompts, not a score for all populations.
- Metabolic Health Screen — checklist with waist-to-height.
- Blood Pressure MAP — mean arterial pressure from systolic and diastolic.
- Blood Alcohol Calculator — BAC from weight, drinks, and time.
- Pregnancy Due Date — Naegele rule with ovulation calculator.
- Ovulation Calculator — fertile window from cycle day.
About this calculator library
Smart Calcs is a text directory of free health calculators. Content supports learning about metabolism, screening, and planning; it is not a substitute for professional medical advice, diagnosis, or treatment. Use results for discussion with qualified clinicians only.