How to use this calculator
Enter adult measurements and choose an activity level representing your whole day, including work and leisure. The result multiplies estimated resting expenditure by that activity factor. Use it as an approximate maintenance scenario; this tool does not prescribe weight-loss or weight-gain targets.
The math behind it
Resting kcal/day = 10 × kg + 6.25 × cm − 5 × age + sex coefficient Estimated maintenance kcal/day = resting kcal/day × activity multiplier Activity scenarios: 1.4, 1.6, 1.8 or 2.2
A worked example
For a 30-year-old using the male equation at 70 kg and 175 cm, resting energy is 1,648.75 kcal/day. A 1.6 multiplier gives an estimated 2,638 kcal/day for maintenance.
Assumptions & precision
This simple model combines Mifflin–St Jeor resting expenditure with approximate activity scenarios informed by physical-activity-level ranges. It is not the FAO or NIDDK model, a measured energy requirement, or a weight-change prediction. Ages 19–78 only; not for pregnancy, breastfeeding or clinical nutrition. Individual needs may differ substantially. Food Calories mean kilocalories (kcal). Inputs use unrounded values internally; results round to whole kcal. No automatic exercise-calorie addition, deficits or diet plans.
A common question
How should I choose an activity level?
Think about movement across a typical whole day, not just workout frequency. The options are assumptions for comparison, not measured personal factors. A clinician or dietitian can help if you need individualized energy guidance.