Health & Fitness
Every equation here is a population regression, which means it describes a group well and any individual approximately. Results are shown as ranges, targets are floored at clinically accepted minimums, and the tools state where the formula stops being valid rather than projecting confidence past its own evidence.
Body Composition
BMI CalculatorBMI with the region's own thresholds applied. India uses lower overweight and obesity cut-offs than the standard WHO values, and almost no competitor applies them.Ideal Body Weight CalculatorHealthy weight as a range rather than a single number. The Devine and Hamwi formulas were built for drug dosing, not for setting personal targets, and they return one number where a range is the honest answer.Body Fat Percentage CalculatorBody fat estimated from tape measurements or BMI. Both methods carry three to five percentage points of error against a proper measurement, so the band matters more than the point estimate.Lean Body Mass CalculatorLean body mass and what it implies for protein and metabolic rate. Where body fat is known, lean mass follows directly; the formulas are estimates for when it is not.Waist-to-Hip Ratio CalculatorWaist to hip ratio, which measures fat distribution rather than quantity. Abdominal fat is more strongly associated with metabolic risk than the same amount carried on the hips.Waist-to-Height Ratio CalculatorWaist to height ratio, with the rule of keeping your waist under half your height. It predicts cardiometabolic outcomes at least as well as BMI, needs no chart, and works across populations where BMI thresholds do not.
Metabolism
BMR CalculatorBasal metabolic rate by Mifflin–St Jeor or Harris–Benedict, presented as a range. A single figure would be false precision: these equations carry roughly ±10% individual error.TDEE CalculatorTotal daily energy expenditure from the Mifflin St Jeor equation and an activity multiplier. The multiplier is the weak link and it is almost always chosen too high, which is the single most common reason a calculated deficit produces no weight loss.
Nutrition
Daily Calorie Needs CalculatorA daily calorie target for a stated rate of loss or gain, with a floor below which the page will not go. Faster is not better: beyond about one percent of body weight a week, the extra loss comes disproportionately from muscle.Macro CalculatorGrams of protein, carbohydrate and fat from a calorie target and a split, with the protein checked against body weight rather than only against the percentage. A percentage split alone can leave protein too low on a small calorie target, which is where it matters most.Protein Intake CalculatorDaily protein for a stated goal, as a range rather than a single figure, distributed across meals. Where body fat is known the calculation runs on lean mass, which matters because protein needs track lean tissue and not total weight.Carb and Fat Intake CalculatorCarbohydrate and fat from whatever calories remain once protein is set, with a fat floor that the split cannot go below. Fixing protein first is the right order: it is the macro with a requirement, and the rest is largely preference.Water Intake CalculatorA daily fluid target from body weight, exercise and climate, separating total fluid from what actually needs drinking. Roughly a fifth of intake comes from food, and coffee and tea count toward the total rather than against it.
Fitness
Calories Burned CalculatorCalories burned from activity, using MET values. The gross figure includes what you would have burned sitting still, so the net figure is the honest one for anyone counting a deficit.MET Value CalculatorEnergy from a MET value directly. MET minutes are the unit physical activity guidelines are written in, with 500 to 1,000 a week the usual target.Heart Rate Zone CalculatorTraining zones by the Karvonen and percentage-of-maximum methods. Karvonen uses heart rate reserve, so it accounts for resting rate and gives higher zone boundaries for a fitter person.Max Heart Rate CalculatorMaximum heart rate estimates, with the error stated. Every formula here has a standard deviation of around ten beats, which is wider than a training zone, so a measured maximum beats any estimate.VO2 Max CalculatorVO2 max estimated from a field test. All three methods are regressions with roughly ten to fifteen percent error, so the useful comparison is against yourself over time rather than against a category boundary.Running Pace CalculatorRunning pace, speed and equivalent times at other distances. Pace is the inverse of speed, so a faster run has a smaller pace number, which is why the two are easy to confuse when comparing.Race Time PredictorRace time predicted from a known result, using the Riegel formula. The prediction assumes training appropriate to the target distance, which is the assumption that makes marathon predictions from 5 km results unreliable.Marathon Split CalculatorMarathon splits for even, negative or positive pacing. Almost every marathon record has been run on a negative or near-even split, and almost every amateur runs a positive one.Cycling Power and Speed CalculatorPower required to ride at a given speed. Aerodynamic drag rises with the cube of speed, so going ten percent faster on the flat needs about a third more power.Swim Pace CalculatorSwim pace per 100 metres. A short course pool flatters times because each turn gives a push off the wall, so short and long course results are not comparable.Steps to Calories and Distance CalculatorCalories from a step count. The 10,000 step target came from a 1960s Japanese pedometer marketing campaign rather than from research, though the health benefits of walking are real.
Strength
One Rep Max CalculatorOne rep max estimated from a set. The formulas agree closely up to about five reps and diverge sharply beyond ten, so a set of three predicts far better than a set of fifteen.Wilks and DOTS Score CalculatorDOTS score for powerlifting totals, which normalises across bodyweight so lifters in different classes can be compared. It replaced the older Wilks coefficient, which was found to disadvantage the lightest and heaviest lifters.
Children
Clinical
Body Surface Area CalculatorBody surface area across the three common formulas. BSA is used for chemotherapy dosing and cardiac index, and the formulas agree within a few percent, which matters when the dose is proportional.Weight-Based Dosage CalculatorWeight-based dosing arithmetic, with the single and daily caps applied and the liquid volume worked out from the concentration on the bottle. It computes what you tell it to compute and does not know the drug.eGFR CalculatorEstimated glomerular filtration rate by the 2021 CKD-EPI equation, which dropped the race coefficient. The number is an estimate with a wide interval and a single reading names no diagnosis, so this page reports the band a result falls in rather than assigning a stage.A1C to Blood Glucose ConverterA1C to estimated average glucose and back, plus the IFCC unit used outside the United States. The relationship is a regression with real scatter, so two people with the same A1C can genuinely differ by twenty or thirty mg/dL in mean glucose.Cholesterol Ratio CalculatorCholesterol ratios and the Friedewald LDL estimate, with non-HDL alongside because it needs no estimation and no fasting. Where triglycerides are above 400 the Friedewald estimate is invalid and this page says so instead of printing it.
More
Smoking Cost CalculatorThe financial cost of smoking, including what the same money would compound to if invested. The compounded figure is usually an order of magnitude larger than the annual spend, which is the point of showing it.Sleep Cycle CalculatorBedtimes that let you wake at the end of a sleep cycle rather than the middle of one. Waking mid-cycle from deep sleep is what produces grogginess even after eight hours.Life Expectancy EstimatorA rough life expectancy from age, showing why the number rises as you get older. Life expectancy at birth averages in everyone who died young, so surviving to any age already puts you above it.