Health & Nutrition
Screening estimates from published formulas, not diagnoses. Each page names the body that published the formula it uses — CDC, Navy, Mifflin-St Jeor — because these figures differ between methods and the method matters more than the decimal places.
Screening estimates from published equations — Mifflin-St Jeor, the US Navy circumference method, the CDC bands. Population-level maths, never a diagnosis.
Body measurements
- Pounds and Ounces ConverterA weight in grams or kilograms as pounds and ounces — the two-unit reading a hospital chart and a kitchen scale actually give.
- Stones and Pounds ConverterA body weight in kilograms as stones and pounds, the way a British scale reads it — with the remainder shown rather than folded into a decimal.
- Body Surface Area CalculatorBody surface area by the Mosteller and Du Bois formulas, the measure chemotherapy and paediatric doses are scaled by.
- Body Shape CalculatorBody shape from bust, waist and hips, with the waist-to-hip and waist-to-height ratios the WHO uses to judge risk.
- GFR CalculatorEstimated glomerular filtration rate by the 2021 CKD-EPI equation — the race-free one — with the CKD stage it falls in.
- Puppy WeightAdult weight from a puppy's weight and age, on growth curves that differ by breed size — small dogs finish at eight months, giant breeds at eighteen.
Body composition
- BMI CalculatorBody mass index from height and weight in either metric or US units, with the CDC category cut-offs.
- Body Fat CalculatorBody fat percentage from tape measurements using the US Navy circumference method, plus lean mass.
- Ideal Weight CalculatorReference weight from height by four standard clinical formulas, and the BMI-healthy range they sit inside.
- Army Body Fat CalculatorThe Army’s waist-to-height assessment that replaced the tape test in July 2026, with the waist measurement the 0.55 standard allows at your height.
- Lean Body Mass CalculatorLean mass by the Boer, James and Hume equations side by side, with the fat mass each implies — the three disagree by kilograms, so the formula is the answer.
- FFMI CalculatorFat-free mass index from weight, height and body fat, with the height-normalised version and the threshold the original study drew.
Energy & nutrition
- TDEE CalculatorHow many calories you burn in a day, from the Mifflin-St Jeor equation and an activity multiplier, with cut and bulk targets beside it.
- Macro CalculatorGrams of protein, carbohydrate and fat from a calorie target and a diet split. With protein per kilogram, the number a split is judged on.
- Calories Burned CalculatorEnergy burned by an activity from its MET value, body weight and duration. Net of what you would have burned sitting still, which trackers leave in.
- Calorie Needs CalculatorDaily calorie target for a weight goal, and the number it becomes after the first five, ten and fifteen pounds come off.
- Weight Loss Timeline CalculatorThe date you reach a goal weight at a given intake, with the deceleration the flat 3,500-calorie rule leaves out.
- BMR CalculatorBasal metabolic rate from the Mifflin-St Jeor, revised Harris-Benedict and Katch-McArdle equations at once, with the disagreement between them shown.
- Protein CalculatorDaily protein from body weight, with the floor the DRI sets and the higher range the training literature uses, kept apart.
- Fat Intake CalculatorHow many grams of fat a day your calorie intake allows, inside the 20-35% range the Dietary Guidelines set, with the saturated fat ceiling separately.
- Steps to Miles CalculatorSteps to miles and kilometres from a stride derived from your height, not the flat 2,000-a-mile pedometers assume — plus what the walk cost in calories.
- Dog Calorie CalculatorDaily calories a dog needs, from the resting energy requirement formula vets use — 70 x weight^0.75 — multiplied by the factor for its life stage.
- A1C CalculatorA1C converted to estimated average glucose in both units, by the ADAG regression, with the wide individual scatter that regression hides.
- LDL CalculatorLDL cholesterol calculated from a lipid panel by both Friedewald and the Martin-Hopkins method, which disagree most where it matters.
Training & recovery
- Water Intake CalculatorDaily fluid target from body weight and exercise, against the NASEM total-water reference intakes.
- Heart Rate Zone CalculatorMaximum heart rate and training zones from age and resting pulse, using Tanaka and the Karvonen reserve method.
- One Rep Max CalculatorYour one-rep max from a set to failure, by all four published formulas at once, with the spread between them and how far they run high.
- Sleep CalculatorWhat time to go to bed to wake at the end of a sleep cycle rather than in the middle of one, counted back from the alarm you have already set.
- VO2 Max CalculatorVO2 max from a Cooper 12-minute run or from resting and maximum heart rate, with what each method can and cannot see.
Pregnancy
- Due Date CalculatorEstimated due date from a last menstrual period or a known conception date, with the current gestational age.
- Ovulation CalculatorOvulation day and the six-day fertile window from your last period, counted back from the next period rather than forward from day 14.
- Period CalculatorYour next six periods from the last one, with the prediction window widening the further out it goes — because cycle length varies month to month.
- Pregnancy Weight Gain CalculatorWhere your weight should be at this point in pregnancy, from the 2009 Institute of Medicine ranges for your pre-pregnancy BMI.
- Conception Date CalculatorWhen conception most likely happened, worked back from a due date or a last period, with the window either side that the single date hides.
- Dog Pregnancy CalculatorWhelping date from the mating date, on the 63-day canine gestation, with the dates each check and each stage of the pregnancy falls due.
Fitness
Dosage
- Dog Chocolate ToxicityTheobromine dose a dog has taken from the type and weight of chocolate eaten, against the published thresholds where signs begin and where they turn serious.
- Corrected CalciumSerum calcium adjusted for albumin by the Payne formula, in both conventional and SI units, with the case where the adjustment misleads.
- ANC CalculatorAbsolute neutrophil count from a white cell count and the differential, with the severity bands and the bands that only count segs.
- Milligrams to Milliliters CalculatorVolume of a liquid that holds a given mass, from the concentration on the label — because milligrams and milliliters only relate through that number.
Cooking & kitchen
Reference charts
- BMI Chart by Weight — 31 rows
- Daily Calories by Body Weight Chart — 23 rows
- Weight Loss Time by Daily Calorie Intake — 14 rows
- Steps to Miles Chart — 22 rows
- Dog Calorie Chart by Weight — 27 rows
- Puppy Growth Chart by Age — 20 rows
- A1C to Blood Glucose Chart — 16 rows