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Fitness Calculators

Every tool below shows its formula, cites its sources and walks the arithmetic in the open — the same way Maddy (NASM-CPT) builds client plans. No email wall, no locked results.

CALORIESTDEE CalculatorMaintenance calories plus fat-loss and muscle-gain targets — Mifflin-St Jeor, arithmetic shown. CALORIESBMR CalculatorResting burn from two validated equations, side by side, with the gap between them shown. CALORIESCalorie Deficit PlannerA goal date, a safe rate capped at 1% of bodyweight per week, and honest warnings. NUTRITIONProtein IntakeDaily grams by goal — the 1.6–2.2 g/kg evidence band, not one magic number. NUTRITIONMacro SplitProtein, fat and carb grams from your calories and goal — protein first, carbs last. NUTRITIONWater IntakeThe honest version — published reference intakes next to the ml/kg heuristic, labeled. STRENGTHOne-Rep MaxEpley and Brzycki side by side, plus training percentages off the average. CONDITIONINGHeart Rate ZonesKarvonen zones from your resting heart rate, with both max-HR formulas compared. CONDITIONINGSteps to CaloriesMET-based conversion from the Compendium — gross and net burn both shown. BODYBMI CalculatorWHO bands plus Asian-population action points — with what BMI cannot see, stated plainly. BODYBody Fat (Navy Tape)The published circumference method — fat mass and lean mass broken out. BODYHealthy Weight RangeA range for your height, not a single number — because one ideal weight is a myth.

The math, shown

Most calculator sites hide the formula and hope you never ask. These tools do the opposite: every page names its equation, cites the published research behind it — Mifflin-St Jeor 1990, Morton 2018, Helms 2014, Tanaka 2001, the WHO reports and more — and expands the arithmetic line by line under your result.

They are also honest about limits. These are population formulas — a starting point, not a prescription. Where the evidence is weak (water intake) or the number is often oversold (BMI, "ideal weight"), the page says so instead of pretending.

These numbers are the first 10% of a plan.

Maddy hand-builds the other 90% — training, food culture, recovery — around your exact body.

Start My Body Scan → 11 questions · 3 min · free · no card yet