- ⚖️Most Used
Calorie Calculator
Calculate your exact daily calorie needs using the Mifflin-St Jeor equation — the gold standard for BMR estimation. Supports metric and imperial units.
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TDEE Calculator
Calculate your Total Daily Energy Expenditure across 5 activity levels. The foundational number for any evidence-based nutrition plan.
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BMI Calculator
Calculate Body Mass Index with a full healthy-weight range breakdown. Includes WHO classification, limitations, and body composition context.
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Calorie Deficit Calculator
Calculate the precise calorie deficit and timeline to reach your target weight. Safe, sustainable, and adjusted for metabolic adaptation.
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Body Fat Calculator
Estimate body fat percentage using the US Navy circumference method — validated and accurate without gym equipment or body fat calipers.
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Ideal Weight Calculator
Calculate your ideal body weight across four peer-reviewed formulas: Hamwi, Miller, Robinson, and Devine — with a personalised healthy range.
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Free nutrition
calculators — science
backed.
Calculate calories, macros, TDEE, BMI, body fat, protein intake, keto macros, and more — instantly, using peer-reviewed formulas from Mifflin-St Jeor, ACSM, ISSN, and USDA. Free forever, no account needed.
Instant results
Every calculator updates live as you type. No loading screens, no button to press — results appear in real time.
Science-backed only
Every formula traces to a named, peer-reviewed source. Mifflin-St Jeor, ACSM, ISSN, USDA — never a black-box algorithm.
Visual & actionable
Colour-coded macro bars, body composition charts, and training percentage tables make results immediately usable.
Permanently free
All 18 calculators, every feature, every update — free forever. No signup, no paywall, no ads in your results.
What are you trying to figure out?
Every nutrition tool you need,
all in one place.
From basic calorie counting to advanced body composition analysis — all calculators are science-backed, instant, and permanently free.
- 🥗Popular
Macro Calculator
Calculate your daily protein, carbohydrate, and fat targets in grams — tailored to your body weight, TDEE, and fitness goal (fat loss, maintenance, or muscle gain).
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Protein Intake Calculator
Find your optimal daily protein target based on body weight and goal. Includes food equivalents, per-meal targets, and ISSN/ACSM evidence-based ranges.
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Keto Macro Calculator
Calculate your personalised ketogenic diet macros — net carbs, protein, and fat — for Standard (SKD), Targeted (TKD), or Cyclical (CKD) protocols.
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BMR Calculator
Calculate your Basal Metabolic Rate using both Mifflin-St Jeor and Harris-Benedict formulas side by side, with organ-level breakdown of where calories go.
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Carb Calculator
Calculate daily carbohydrate intake for Standard, Low-Carb, Keto, or Athlete diet types. Includes GI guide, fibre targets, and food reference tables.
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Fat Intake Calculator
Calculate your daily fat target with a saturated vs unsaturated split. Includes omega-3 vs omega-6 guidance, food sources, and heart-health context.
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Water Intake Calculator
Calculate your optimal daily hydration target using the 35 ml/kg baseline adjusted for exercise duration and climate — with an hourly schedule.
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One Rep Max Calculator
Estimate your 1RM using Epley, Brzycki, and Lander formulas. Includes a full training percentage table with rep ranges and training zones.
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Calories Burned Calculator
Calculate calories burned during 15+ exercise types using MET values from the Compendium of Physical Activities. Includes food equivalents and EPOC context.
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- 🔬Advanced
Recipe Nutrition Calculator
Analyse the full macro and micronutrient breakdown of any recipe ingredient-by-ingredient using USDA FoodData Central — instant, accurate, and free.
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Body Metrics Calculator
Calculate Waist-to-Hip Ratio, Waist-to-Height Ratio, and Body Roundness Index (BRI) for a comprehensive cardiovascular and metabolic health risk profile.
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Fasting Timer
Time your intermittent fast in real-time with metabolic phase tracking for 16:8, 18:6, 20:4, and OMAD protocols — complete with science-backed phase descriptions.
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Results in under 60 seconds.
Pick your calculator
Choose from 18 free tools across 4 categories — body & weight, macros & diet, fitness, and advanced metrics. All on one platform.
Enter your measurements
Input height, weight, age, and activity level. All calculators support both metric (kg/cm) and imperial (lbs/ft/in) units.
Get instant results
Results appear live as you type — no button press, no loading screen. Follow in-tool links to build your full nutrition picture.
Every result traces to a named, peer-reviewed source.
MacrosMeasure never uses proprietary algorithms or black-box scoring. Every calculation uses a published, citable formula — Mifflin-St Jeor for BMR, ACSM MET values for calorie burn, ISSN guidelines for protein, and USDA FoodData Central for nutrition data.
Results are mathematical estimates based on validated population equations, not clinical diagnoses. For personalised medical nutrition therapy, consult a registered dietitian.
All formulas are reviewed against their original published source annually. Mifflin-St Jeor (1990), US Navy method (Hodgdon & Beckett, 1984), Epley (1985), ACSM Compendium (Ainsworth et al., 2011). Read our methodology →
Nutrition questions, answered instantly
Use the Mifflin-St Jeor BMR equation — multiply by your activity factor to get TDEE. Our Calorie Calculator does this instantly. Most adults need 1,600-3,000 kcal/day.
Calculate calories →Macros (macronutrients) are protein, carbohydrates, and fat. Your macro targets are a percentage split of your daily calorie needs, adjusted for your goal (fat loss, muscle gain, maintenance).
Calculate macros →TDEE (Total Daily Energy Expenditure) is the total calories you burn daily — BMR x activity factor. It is the most important number for weight management and nutrition planning.
Calculate TDEE →Research supports 1.6-2.4 g per kg bodyweight for most active adults. Sedentary individuals need 0.8-1.0 g/kg. Higher intake (1.8-2.4 g/kg) is recommended during fat loss to preserve muscle.
Calculate protein →The US Navy circumference method uses neck, waist, and hip measurements to estimate body fat — no calipers or equipment needed. Accurate to within ±3% for most people.
Calculate body fat →Keto fixes net carbs at 20-50g/day to induce ketosis, then allocates remaining calories to fat (65-80%) and protein (15-25%). Standard macros allocate carbs as 45-65% of calories.
Calculate keto macros →Explore by nutrition topic
Our calculators are organised around the most important questions in nutrition science.
Daily calorie needs, TDEE, calorie deficit, and calorie burn — the complete energy balance toolkit.
Full macro targets, protein, carbs, fat, and ketogenic diet planning based on your body and goal.
BMI, body fat percentage, ideal weight, and advanced body shape metrics for health risk assessment.
One rep max, calories burned by activity, water intake, and intermittent fasting protocol tracking.
Take control of your nutrition today.
All 18 calculators — from the calorie calculator to the keto macro calculator — are free, instant, and require no account or subscription.
Free forever · No signup required · Results in under 60 seconds · Science-backed formulas