HomeHealth & Fitness

Health & Fitness Calculators

24+ free tools, updated for 2025-26. No sign-up required.

Period Calculator
Predict your next period and track your menstrual cycle from your last start date.
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Chronological Age Calculator
Calculate your exact age in years, months, and days from your date of birth.
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Starbucks Calorie Calculator
Find the calorie count for any Starbucks drink or food item.
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A1C Calculator
Convert average blood glucose levels to an estimated A1C percentage.
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ABV Calculator
Calculate alcohol by volume (ABV) for homebrew beer, wine, or mead.
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Corrected Calcium Calculator
Calculate albumin-corrected serum calcium from lab values.
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FFMI Calculator
Calculate Fat-Free Mass Index to assess muscle development for athletes.
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Baby Percentile Calculator
Check your baby's weight, height, and head circumference percentile by age.
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Puppy Weight Calculator
Predict your puppy's adult weight based on breed and current age.
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VO2 Max Calculator
Estimate your aerobic capacity and cardiorespiratory fitness level.
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Anion Gap Calculator
Calculate serum anion gap to help diagnose metabolic acidosis causes.
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APFT Body Fat Calculator
Calculate body fat percentage using the US Army tape test method.
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Blood Alcohol Content Calculator
Estimate your BAC based on number of drinks, body weight, and time elapsed.
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Dog Weight Calculator
Determine whether your dog is at a healthy weight for their breed and age.
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Peptide Dosage Calculator
Calculate peptide dose in mcg from vial concentration and desired amount.
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Power to Weight Ratio Calculator
Calculate your power-to-weight ratio in watts per kilogram for cycling and fitness.
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McDonald's Calorie Calculator
Look up the calorie and nutrition information for any McDonald's menu item.
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Panda Express Calorie Calculator
Find calories and nutrition data for Panda Express entrees and sides.
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Cava Calorie Calculator
Build your Cava bowl and get the full calorie and macro breakdown.
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Dog Pregnancy Calculator
Estimate your dog's due date and pregnancy milestones from the breeding date.
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Cattle Gestation Calculator
Calculate the expected calving date based on the breeding or conception date.
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Bike Calories Calculator
Estimate calories burned cycling based on speed, distance, and body weight.
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About Health & Fitness Calculators

Health calculators help you track key medical and fitness metrics using clinically recognized formulas. Whether you are monitoring a chronic condition like diabetes, planning a pregnancy, or tracking your baby's growth against WHO standards, having accurate numbers helps you have better conversations with your healthcare provider and understand your own health more clearly.

Our health tools are built around peer-reviewed reference data — WHO growth charts for pediatric measurements, the Nathan equation for A1C interpretation, and the Payne formula for corrected calcium. None of these tools replace medical advice, but they give you a clear, quantitative starting point before a doctor's appointment.

What You Can Calculate

  • Convert average blood glucose to estimated A1C percentage
  • Predict next period date and fertile window from cycle length
  • Check baby weight percentile against WHO growth-for-age standards
  • Calculate corrected calcium for patients with low albumin
  • Predict adult dog weight from a puppy weigh-in
  • Estimate whelping date and pregnancy milestones for dogs

Frequently Asked Questions

Our calculators use validated clinical formulas: the Nathan equation (ADA 2008) for A1C conversion, the Payne formula for corrected calcium, and WHO Multicentre Growth Reference Study data for pediatric percentiles. Results are consistent with what a clinical calculator would produce, but they are estimates. Always confirm results with a licensed healthcare provider before making medical decisions.

Why Use CalculatorFlux's Health & Fitness Calculators?

Instant results
No loading screens. Results update as you type, with no server round-trip needed.
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Private by design
We store no data, require no sign-up, and track no personal information from your calculations.
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Always current
Tax rates, clinical reference data, and formulas are reviewed and updated every year.

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