These guides help you get more out of the FIT TOOLS calculators. Understanding the reasoning behind each number lets you turn a calculator's output into decisions for your own training. Every article ends with links to the relevant calculators.
What Is 1RM? Estimating It and Using %1RM to Set Training Intensity
What one-rep max means, the estimation formulas, goal-based %1RM zones, and how to combine it with RPE/RIR — with a step-by-step example of choosing your working weight.
Read the article NutritionProtein for Muscle: How Much You Need, When, and From What
Daily intake per kg of bodyweight, splitting into 20–40 g servings, animal vs. plant quality, and where protein fits within your PFC balance — including cutting and bulking.
Read the article NutritionWhat Is Calorie Balance? How Intake vs. Expenditure Changes Your Weight
How energy balance (intake minus expenditure) drives weight change, the parts of TDEE, the ~7,200 kcal per kg rule of thumb, and sustainable rates of loss and gain — with worked examples.
Read the article Body CompositionBMI vs. Body Fat Percentage: What's the Difference and How to Read Your Body Composition
How BMI (height and weight only) differs from body fat percentage (what your weight is made of), why muscular people score high on BMI, and how FFMI fits in.
Read the article NutritionBMR and TDEE Explained: The Difference and How to Calculate Them
How BMR (resting burn) differs from TDEE (total daily burn), how to calculate them with the Mifflin-St Jeor equation, how to pick an activity factor (1.2 to 1.9), and how to set calories for your goal.
Read the article NutritionWhat Is Macro Balance (PFC)? Roles of the Three Macronutrients and How to Calculate Them
The role and calories per gram of protein, fat and carbs, target ratios by goal (fat loss, maintenance, muscle gain), and how to split a calorie target into grams of each, with a worked example.
Read the article NutritionHydration and Electrolytes: How Much Water You Need and How to Drink Around Training
How much water you need per day (weight × 30–40 mL), how to gauge sweat loss, the role of electrolytes (sodium, potassium), and how to hydrate before, during and after training, with cautions.
Read the article RecoverySleep and Recovery: How Much Sleep You Need and How to Use Sleep Cycles for Training
The role of sleep in muscle recovery and growth, how much sleep you need (7–9 hours for adults), how the ~90-minute sleep cycle works, and how to build habits that improve recovery sleep.
Read the article