Health Calculators

About CalcFit Health Calculators

CalcFit Health Calculators is a collection of accurate, privacy-friendly online tools that help you understand key health, fitness, and lifestyle metrics instantly. Every calculator uses evidence-based formulas and medical or scientific references — from BMI, BMR, and TDEE to blood pressure, kidney function, and fertility tracking — plus practical everyday tools for alcohol units, added sugar, sodium, fiber intake, walking calories, and stress/burnout self-screening — all designed for speed, clarity, and zero data storage.

Whether you want to calculate BMI, estimate your Basal Metabolic Rate (BMR) and calorie needs (TDEE), plan a calorie deficit and macros, monitor heart-rate zones, VO₂ Max, and sleep quality, or even forecast fertile days and financial savings from quitting smoking — CalcFit provides simple, accurate, and fast calculators for every goal.

What You Can Calculate

• Body Metrics: BMI, Body Fat %, LBM, Ideal Weight, BSA
• Metabolism & Energy: BMR, TDEE, Calorie, Calorie Deficit, Macros
• Lifestyle & Recovery: Water Intake, Sleep, Caffeine Intake, Intermittent Fasting schedule, Quit Smoking Savings, Alcohol Units, Sugar Intake, Sodium Intake, Fiber Intake, Stress / Burnout Screening
• Reproductive Health: Ovulation & Fertile Window, Pregnancy Due Date, BBT (Basal Body Temperature) / Ovulation Tracker
• Cardio & Performance: Heart Rate Zones, VO₂ Max, Resting Heart Rate (RHR), Running Pace, Calories Burned Running, Calories Burned Walking, Steps → Calories, Fitness Age
• Strength: 1RM (One-Rep Max) with training-percentage tables
• Vitals & Clinical: Blood Pressure Category, MAP (Mean Arterial Pressure), Cholesterol Ratio (HDL/LDL/Total/TG), eGFR (CKD-EPI 2021), Life Expectancy (educational)
• Glycemic Calculators: Glycemic Index (GI) & Glycemic Load (GL) per food and per meal
• Specialized: Waist-to-Hip Ratio (WHR), Waist-to-Height Ratio (WHtR), BAC (Blood Alcohol Content)

Formulas We Use

• BMR: Mifflin–St Jeor; TDEE: standard activity multipliers
• Body Fat %: U.S. Navy method; LBM: Boer
• BSA: Mosteller
• 1RM: Epley, Brzycki, Lombardi, O’Conner, Mayhew, Wathan
• Running kcal: MET values (Compendium) by speed, with interpolation
• Walking kcal: standard MET formula (kcal = MET × 3.5 × weight(kg) ÷ 200 × minutes); MET chosen by walking speed
• Blood Pressure: categorization by AHA ranges
• GI/GL: GL = (GI × available carbs g) ÷ 100; GI Low/Medium/High categories
• Fiber Intake: AI targets by age/sex or rule of 14 g / 1000 kcal; outputs total, target, % of target, gap/surplus
• Sodium / Salt: Na ↔ NaCl conversion (salt [g] = Na [g] × 2.5); comparison vs 1500–2300 mg/day limits
• Sugar Intake: total added sugars (g) vs WHO/AHA limits; 1 tsp ≈ 4 g
• Alcohol Units: units = (volume × %ABV × 0.8) ÷ 10 (UK); converted to drinks/day and weekly totals
• Resting Heart Rate (RHR): reference ranges by bpm; optional VO₂max estimate via Uth–Sørensen formula (15.3 × HRmax/RHR)
• Fitness Age: based on chronological age adjusted by RHR, VO₂max, BMI, and activity level
• Stress / Burnout: 10-item Likert 0–4; total score 0–40 with bands: Low (0–13), Moderate (14–26), High (27–40)
• BBT / Ovulation: coverline = (highest of previous 6) + 0.05 °C; 3 high temps above coverline ⇒ ovulation ≈ day before first rise
• Pregnancy Due Date: Naegele’s Rule
• Life Expectancy: educational longevity model based on population averages and lifestyle modifiers
• eGFR: CKD-EPI 2021 (race-free)
• Cholesterol: Total/HDL, LDL/HDL, TG/HDL ratios; mg/dL ↔ mmol/L
• Smoking Savings: daily = (cigarettes/day ÷ pack size) × price/pack

All calculators provide estimates based on established medical and scientific models. Results are for educational purposes and should not replace professional medical advice or diagnosis.

No accounts, no tracking, no stored data — all calculations run locally in your browser. You get fast, private, and reliable results to make smarter health and lifestyle decisions.

FAQ – CalcFit

• Are CalcFit calculators accurate?
  Yes—each tool uses evidence-based formulas and widely referenced guidelines; see the References section on each page.
• Do you save or track my inputs?
  No. Calculations run locally in your browser and we don’t store form inputs on our servers.
• Is this medical advice?
  No. Results are educational estimates and are not a substitute for professional medical advice, diagnosis, or treatment.
• Which units are supported?
  Metric and US units (cm/ft+in, kg/lb, etc.), with instant conversion where applicable.
• Where do your formulas come from?
  From peer-reviewed research and established clinical guidelines (e.g., Mifflin-St Jeor, CKD-EPI 2021, AHA-style BP ranges). Each calculator lists its sources.
• Does CalcFit work on mobile?
  Yes. All calculators are optimized for fast, mobile-friendly use and low layout shift (CLS).
• Do you use ads or affiliate links?
  We may show privacy-respecting ads/affiliate links. Third-party scripts load only with consent where required; affiliate clicks leave our site.
• Are results valid outside the US?
  Formulas are international, but local clinical ranges can differ. Always interpret results in your own healthcare context.
• How often are calculators updated?
  We review content and formulas periodically and update when new evidence or standards emerge.
• Can I request a new calculator?
  Yes—send suggestions via the Contact page. We prioritize high-value tools based on user demand and evidence availability.

Disclaimer

The tools provided on this site are intended for educational and informational purposes only and are not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified health provider with any questions you may have about a medical condition. If you think you may have a medical emergency, call your local emergency number immediately.