How this calculator works
Resting energy is estimated with the Mifflin-St Jeor equation for healthy adults; this tool accepts ages 15 to 100, though the original study covered ages 19 to 78, then multiplied by a physical activity level factor: 1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 very active, 1.9 extra active. These conventional multipliers range from desk work with little exercise to daily hard exercise plus a physical job. They exclude pregnancy, lactation, illness and athletic extremes, and self-reported activity is often optimistic, so treat the result as a starting point to adjust from. The result is an estimate for information only and is not medical advice.
Formula
TDEE = BMR x activity factor, where BMR comes from Mifflin-St Jeor (see the BMR calculator) and the factor is 1.2, 1.375, 1.55, 1.725 or 1.9.
Worked example
A 30-year-old man weighing 80 kg at 180 cm has BMR 1780 kcal/day. Sedentary: 1780 x 1.2 = 2136 kcal/day. Moderately active: 1780 x 1.55 = 2759 kcal/day.
Advertisement
Frequently asked questions
Which activity level should I choose?
Pick the level that describes most of your week, not your best day. Exercise counts, but so does a physical job; activity categories are approximate and do not measure individual energy use.
Why does my tracker show a different number?
Devices measure movement and estimate rest differently. Both methods have individual errors and should be interpreted as estimates.
Can I eat my TDEE exactly and stay stable?
That is the idea, but day-to-day needs vary. The calculated maintenance value is a rough starting estimate, not a personalised diet prescription.