How the math works
We estimate your baseline daily calories (TDEE) using the Mifflin-St Jeor equation, which adjusts for weight, height, age, and activity. Then we add the standard breastfeeding bonus: +330 kcal/day for the first 6 months of exclusive nursing, +400 kcal/day after, and about +165 kcal/day for partial / combination feeding.
These are averages from US/UK guidance (Institute of Medicine, NHS). Real needs swing with growth spurts, sleep, postpartum recovery, and how much milk your baby is taking. The number is a starting point - hunger is a more reliable day-to-day signal.
Where calories come from matters
Aim for protein at every meal, iron and B12 (postpartum + nursing both raise needs), calcium and vitamin D for bone density, and 2.5-3 L of water a day. If you're tracking pregnancy weeks alongside, see the pregnancy week calculator.
Frequently asked questions
How many extra calories do I need while breastfeeding?
The standard guidance is about 330 extra kcal/day for exclusive breastfeeding in the first 6 months and 400 after that. Partial breastfeeding needs less - roughly half. Individual needs vary; use this as a starting point.
Should I diet to lose baby weight while breastfeeding?
Mild calorie deficits (eating slightly less than your nursing target) generally don't affect milk supply, but aggressive dieting can. Most experts suggest waiting at least 6-8 weeks postpartum before any deliberate weight loss, and prioritizing nutrient density over calorie cutting.
Why do I feel hungrier some days?
Cluster feeds, growth spurts, and your baby's appetite all change demand. Hunger is a reliable signal - eat to it.
These calculators give estimates based on cycle averages and standard formulas. They are for general information only and are not medical advice. For anything concerning your health or pregnancy, talk to a qualified healthcare provider.