Pregnancy Calorie Needs Calculator
Daily calories during pregnancy by trimester — Mifflin-St Jeor maintenance plus the recommended extra 0, 340 or 450 kcal.
How it works
BMR (Mifflin-St Jeor) × activity + 0 / 340 / 450 kcal by trimester (+ ~300 kcal for twins)
Energy needs barely change in the first trimester. The Institute of Medicine recommends about 340 extra calories a day in the second trimester and 450 in the third, when the baby gains most weight. Twins add roughly another 300. Quality matters more than quantity: folate, iron, calcium, iodine and protein all rise.
Worked example
Age 30, 163 cm, 62 kg, lightly active: BMR 1,335 → maintenance 1,836 → second trimester about 2,180 kcal.
Frequently asked questions
What if I started overweight?
The additions are the same but total weight-gain targets are lower; discuss a plan with your care team rather than cutting calories.
Is 340 kcal a lot?
A glass of milk plus a peanut-butter sandwich, or a bowl of yoghurt with granola and fruit.
Related calculators
Educational estimate only — your midwife or doctor will confirm dates and advice for your pregnancy.