Calories and energy needs

Enter height in cm, weight in kg, whole years of age, the formula sex category `male` or `female`, one of five activity levels and one of three goals. Valid ranges are 120–230 cm, 35–300 kg and 18–100 years. Outside them, the service returns no result.

The tool displays estimated resting energy, a maintenance range and the range for the selected goal. It also calculates an internal total-energy midpoint to form the visible ranges, but does not present that midpoint as a supposedly exact single value. All values are kcal per day.

Resting and total energy expenditure are model values in this calculator. An equation and activity factor do not replace indirect calorimetry or observation of everyday life.

The only difference between the two service branches is the constant +5 or −161. The result is called estimated resting energy in the tool; it is neither measured basal metabolism nor a direct daily intake instruction.

PAL represents all daily activity together: routine, work, household tasks, travel, leisure movement and training share one factor. Training is not added again as separate exercise calories. The selectable factors are sedentary 1.4, lightly active 1.5, moderately active 1.6, very active 1.8 and exceptionally active 2.0.

The level is a model assumption, not a universally fitting classification. With `exceptional`, the service always issues `EXTREME_ACTIVITY_REQUIRES_CAREFUL_SELECTION`, because factor 2.0 presumes exceptionally high total activity.

Maintenance is always displayed. The selected goal adds its own visible range; for `maintain`, it is the same range. The maintenance and goal factors are project specifications, not literal recommendations of Mifflin, EFSA or DGE.

The service rounds displayed resting energy mathematically to the nearest 10 kcal and each range edge to the nearest 25 kcal, after calculating at full precision. If a rounded loss-range lower edge falls below unrounded resting energy, it issues `GOAL_RANGE_BELOW_RESTING_ENERGY`; it does not replace the value with an invented minimum.

Enter 180 cm, 80 kg, age 30, `male`, `moderate` and `maintain`. The service calculates 10 × 80 + 6.25 × 180 − 5 × 30 + 5 = 1,780 kcal/day estimated resting energy. Rounding to 10 kcal still displays 1,780 kcal.

For `moderate`, it uses PAL 1.6: the internal midpoint is 1,780 × 1.6 = 2,848 kcal. The maintenance edges are 2,705.6 and 2,990.4 kcal, displayed after 25-kcal rounding as 2,700–3,000 kcal/day. `maintain` returns that same range and no warning for these inputs.

Enter 165 cm, 65 kg, age 30, `female`, `light` and `lose-slowly`. The equation returns 10 × 65 + 6.25 × 165 − 5 × 30 − 161 = 1,370.25 kcal, displayed as 1,370 kcal.

With PAL 1.5, the internal midpoint is 2,055.375 kcal. For `lose-slowly`, the service calculates 85%–90%: 1,747.06875 and 1,849.8375 kcal, displayed as 1,750–1,850 kcal/day after 25-kcal rounding. This is a calculation scenario, not a prediction of weight change or a prescription of what to eat.

The calculator creates no meal plan, macronutrient distribution, food or exercise-calorie calculation, target weight or time forecast. It neither enters nor calculates body fat, fat-free mass or Katch-McArdle, and has no technical dependency on the Body Metrics or BMI calculators.

According to the module README, it is not intended for minors; pregnancy or lactation; eating disorders or their history; conditions with a relevant effect on energy needs; medically prescribed nutrition; professionally supervised elite sport; or supervised therapy and medication cases.

The ranges are estimates for healthy adults within the implemented input limits. They do not replace measurement, diagnosis, treatment, or individual nutritional or medical advice.