Pregnancy Calorie Needs

About this calculator

Calorie needs in pregnancy build on your pre-pregnancy baseline in stages, not with a single flat number added from day one: most clinical guidelines (including those from ACOG and the Institute of Medicine) suggest no extra calories in the first trimester, roughly +340 kcal/day in the second trimester, and roughly +450 kcal/day in the third, reflecting the accelerating energy cost of fetal growth as pregnancy progresses.

These trimester-based additions matter because gaining too little or too much weight during pregnancy both carry documented risks — under-eating is linked to lower birth weight, while excess intake beyond these targets is associated with gestational diabetes and delivery complications — so obstetricians and dietitians use trimester-adjusted estimates rather than a single “eating for two” rule of thumb, which historically overshot actual needs by a wide margin.

Enter your baseline daily calories and current trimester, and this calculator adds the appropriate extra calories for that stage, giving you an estimated daily target. This tool is informational and does not replace guidance from your prenatal care provider.