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nutrition/calculate-calorie-needs·B · moderate·~2 min read

How to calculate your calorie needs

Your needs consist mainly of basal metabolic rateBasal metabolic rate The energy your body uses per day at complete rest, for breathing, heart, brain and organs. More in the glossary → and movement. Equations like Mifflin-St Jeor give a good starting point, but are often 10% or more off for individuals. It only gets accurate when you watch your weight and food for a few weeks and adjust.

// What the research shows

Total expenditure is made up of basal metabolic rate (energy at rest), the thermic effect of food (roughly 10%) and movement, meaning training and daily life. Basal metabolic rate usually accounts for 60 to 75% in the general population (O'Neill et al., 2023). Equations can estimate it. In a systematic reviewSystematic review A review that searches for and evaluates all relevant studies on a question using fixed, predefined rules. More in the glossary → (Frankenfield et al., 2005), the Mifflin-St Jeor equation predicted measured resting metabolic rate within 10% in more people than other equations and had the narrowest error range. In athletes, a meta-analysisMeta-analysis A study of studies: the results of many individual studies are pooled statistically. More in the glossary → found the Ten-Haaf equation performed best, with about 80% of people within 10%, while other equations ranged from 41 to 64% (O'Neill et al., 2023). Basal metabolic rate is then multiplied by a physical activity levelPhysical activity level (PAL) The number you multiply basal metabolic rate by to estimate total expenditure. Sedentary about 1.4 to 1.7, very active 2.0 and above. More in the glossary → (PAL). FAO, WHO and UNU (2004) distinguish 1.40 to 1.69 for a sedentary or lightly active lifestyle, 1.70 to 1.99 for an active one and 2.00 to 2.39 for a vigorously active one.

What makes up daily energy needsbasal metabolism60–75 %digestion≈10 %movement & trainingvariable
Basal metabolism–
Maintenance (starting point)–
Bulk (+5%)–
Fig. · Estimate your needs Schematic. The calculator estimates basal metabolism with the Mifflin-St Jeor equation and the rest via the activity factor (FAO/WHO/UNU, 2004). The result is a starting point, not exact needs.

// In practice

  • Use the equation as a starting point (calculator in the figure) and eat about that much for 2 to 3 weeks. Weigh yourself daily and look at the weekly average.
  • If the average stays the same, you've found your maintenance. If it rises or falls, adjust in steps of about 100 to 200 kcal.
  • Be conservative with the activity factor: if you sit a lot and train three times a week, you're usually still in the lower range.

// Limitations & open questions

All equations only estimate. Muscle mass, genes, age and health shift your needs, and older adults and many population groups were underrepresented in validation studies (Frankenfield et al., 2005). The activity factor is also only a rough category.

// Sources

last reviewed: 2026-11-14

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