Calculation Methodology

Follow the calculation from body measurements to daily energy and macro targets.

Inputs and Units

Enter age in years, weight and height, the equation sex parameter, activity and goal. Home accepts ages 18–100, 30–350 kg and 100–250 cm; these input limits are not proof of suitability. The sex field selects an equation constant.

Resting Energy Estimate

Resting energy = 10 × kg + 6.25 × cm − 5 × age + 5 for male, or −161 for female. The interface may call this BMR, but it predicts resting energy; it does not measure basal metabolism under controlled conditions.

Activity Factors

• Sedentary · 1.2: mostly seated work and little movement.
• Lightly active · 1.375: seated work with some walking or light activity.
• Moderately active · 1.55: regular activity across the week.
• Very active · 1.725: substantial daily movement and demanding exercise.
• Extra active · 1.9: physical work combined with demanding training.

Multiply resting energy by the selected factor. These are approximate application planning multipliers, not factors validated by the resting-energy paper. Choosing an activity level.

How Goals Change the Target

Lose Fat uses maintenance × 0.90; Maintain Weight × 1.00; Build Muscle × 1.05. These presets are starting choices, not promises of a weight-change rate. The home calculation does not add a personalized safety floor.

How Protein, Carbs, and Fat Are Set

The default split is 25% protein, 50% carbohydrate, 25% fat by energy. Divide each energy share by 4, 4 and 9 kcal/g respectively. This starting point is not an individually optimal ratio. The protein tool separately offers a custom grams-per-kg target or an exercising-adult reference range; it does not automatically replace home protein.

Worked Example

Public demonstration: male, 29 years, 183 cm, 78 kg. Resting energy = 1783.75 kcal/day. At 1.55, maintenance = 2764.8125 kcal/day (about 2765). Maintaining at 25/50/25 gives 172.8 g protein, 345.6 g carbs and 76.8 g fat.

Rounding and Unit Conversion

Calculations keep unrounded targets. Calories display as whole numbers and macros to at most one decimal. Home converts pounds using 2.20462262185 lb/kg; tools use 0.45359237 kg/lb. A foot is 30.48 cm and an inch 2.54 cm. Displayed inputs can be rounded to two decimals.

Intended Use and Limitations

Adult planning estimates are not medical prescriptions or measurements. Children, pregnancy, breastfeeding and medical conditions are not individually modeled. Macro matching does not assess diet quality or micronutrients.

Sources and Updates

Mifflin et al. (1990): resting energy study. This source supports the equation, not our activity or goal presets.

This explanation was checked against the application calculation code. Software checks are distinct from professional nutrition review. Why results differ · TDEE calculator.

Content revised November 4, 2026.