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Health and Fitness Calculators

Body measures, nutrition, pregnancy and fitness tools, each with its formula and its limits.

By Adzita Editorial Team · Updated 2026-11-03 · How we build and check our tools

These tools estimate body measures, energy needs, fertility and pregnancy dates, training intensity and more. Each page names the formula and its source, shows a worked example, and says where the estimate can mislead. They are educational and do not replace a clinician.

BMI CalculatorBMI with WHO and Asian cut-offs, healthy weight range and waist-to-height ratio.Calorie CalculatorDaily calories, goal target and starting macros, with a simple adjust-as-you-go rule.BMR CalculatorResting energy by three formulas, side by side.Body Fat CalculatorUS Navy method estimate with fat and lean mass.Ideal Weight CalculatorFour classic formulas plus a BMI-based healthy range.Age CalculatorExact age in years, months and days, with days to your next birthday.Macro CalculatorSplit a calorie target into grams of protein, fat and carbohydrate by goal and style.Pace CalculatorSolve for pace, time or distance and see speed plus 5K to marathon split times.Pregnancy CalculatorEstimated due date, weeks and days pregnant, and trimester from your last period.Due Date CalculatorEstimate a due date from the last period, conception date or IVF embryo transfer date.Conception CalculatorEstimate the likely conception date and fertile window from a due date or last period.Ovulation CalculatorEstimate ovulation day, the fertile window and the next period from your cycle.Period CalculatorPredict upcoming period start and end dates, with estimated ovulation, from your cycle.Pregnancy Weight Gain CalculatorIOM total and weekly weight gain ranges for a single pregnancy, based on pre-pregnancy BMI.GFR CalculatorEstimate eGFR from serum creatinine, age and sex with the CKD-EPI 2021 equation (adults).One Rep Max CalculatorEstimate your one rep max from a submaximal set with Epley, Brzycki and Lander, plus percentages.Target Heart Rate CalculatorMaximum heart rate, exercise zones and Karvonen targets from age and resting pulse.Protein CalculatorDaily protein in grams per kg of body weight for general health, older age, endurance and strength.Lean Body Mass CalculatorEstimate lean mass and fat mass from height, weight and sex using Boer, James and Hume formulas.Healthy Weight CalculatorWeight range for your height from BMI 18.5 to 24.9, with the Asian 22.9 cut-off option.Waist-to-Height Ratio CalculatorWaist divided by height, with risk bands and the waist size for a ratio of 0.5.Waist-to-Hip Ratio CalculatorWaist divided by hip with the WHO abdominal obesity thresholds of 0.90 for men and 0.85 for women.Calories Burned CalculatorEstimate kilocalories burned for walking, running, cycling and more with MET x kg x hours.Sleep CalculatorBedtimes or wake times that line up with 90-minute sleep cycles, plus time to fall asleep.Body Surface Area CalculatorBSA in square metres from height and weight with Mosteller, Du Bois and Haycock formulas.VO2 Max CalculatorEstimate VO2 max from the Cooper 12-minute run or the heart rate ratio (Uth) method.

How to use the numbers well

  1. Use one formula consistently so changes mean something.
  2. Judge progress over two to four weeks of averages, not single days.
  3. Combine measures: BMI, waist, body fat and how you feel.
  4. Recalculate after each 5 kg change.
  5. Take blood pressure, glucose and cholesterol results to a clinician; calculators cannot replace them.

A sensible order for the core body tools: age, BMI, body fat, BMR, calories, then ideal weight.

Medical disclaimer: This tool is for education and general planning. It is not medical advice and does not diagnose any condition. If you are pregnant, under 18, have an eating-disorder history or a medical condition, speak to a doctor or registered dietitian before changing your diet or exercise.