How much protein you really need, how many calories your body burns, and what BMI does and does not tell you: these guides turn the numbers behind the calculators into plain, evidence-based answers. Every figure is sourced from research and health bodies, and each guide links the tool so you can run your own numbers.
How Much Protein Do You Need Per Day?
Work out how much protein per day you need from your bodyweight and activity level, with the official RDA, athlete ranges, and a worked example.
Protein Per Kg of Body Weight: What the Ranges Really Mean
Protein per kg of body weight, explained: the 0.8 to 2.2 g/kg ranges, who each fits, total vs lean mass, plus worked examples at 60, 80 and 100 kg.
How Much Protein to Build Muscle?
Protein for muscle gain explained: aim for 1.6 to 2.2 g/kg, why total intake wins, how to split meals, and why you also need a surplus and training.
How Much Protein Should You Eat to Lose Weight?
How much protein to lose weight: why a higher target of 1.6 to 2.4 g/kg in a deficit protects muscle, curbs hunger, and burns more energy.
How Many Calories Do You Need? BMR and TDEE Explained
Learn how a calorie calculator estimates your daily needs using the Mifflin-St Jeor BMR formula, activity multipliers, and TDEE, with a worked example.
BMR and TDEE: How Many Calories You Burn
What is BMR and TDEE? Learn how your body burns calories at rest, the three formulas, the activity factors, and how accurate the numbers really are.
What Is a Healthy BMI (and What It Misses)
What is a healthy BMI? See the formula, the WHO categories, a worked example, and the real limits of BMI as a health screening tool.
BMI vs Body Fat Percentage: Which Matters
BMI vs body fat percentage: what each number really measures, why they disagree, how to measure body fat at home, and healthy ranges by sex.
How Much Water Should You Drink a Day?
How much water should you drink a day? See the official baselines, the truth about 8 glasses, and how your body, activity and climate change the answer.
Tools in this guide
Estimate your daily protein needs from your body weight and goal, from general health to building muscle or losing fat. Metric and imperial units.
Estimate your daily calorie needs (BMR and TDEE) from your sex, age, height, weight and activity level, with targets for losing, maintaining or gaining weight.
Calculate your Body Mass Index from weight and height in metric or imperial units. See your WHO category, your healthy weight range and an age-based reference.
Estimate your basal metabolic rate, the calories your body burns at rest, with the Mifflin-St Jeor, Harris-Benedict and Katch-McArdle equations, plus your TDEE for your activity level.
Estimate your body fat percentage with the US Navy tape method or a BMI-based formula, plus your fat mass and lean mass, in metric or imperial units.
Estimate how much water to drink each day from your body weight, exercise and climate, with the amount in liters, cups, ounces and glasses, alongside the EFSA and US health baselines.