About the Pregnancy & Breastfeeding Calorie Calculator
This pregnancy and breastfeeding calorie calculator estimates how many calories you need per day at each stage: before pregnancy, in each trimester and while breastfeeding. It first works out your usual energy needs from your pre-pregnancy weight, height, age and activity level, then adds the extra energy for the stage: nothing extra in the first trimester, about 340 kcal a day in the second and about 450 kcal in the third (ACOG’s guidance for people who started pregnancy at a healthy weight), and 400 kcal a day for exclusive breastfeeding in the first 6 months or 380 kcal from 7–12 months (National Academies Dietary Reference Intakes for Energy, 2023).
It is for expecting and new mothers who want a realistic daily target rather than the myth of “eating for two”, and for dietitians, doulas and partners planning meals. The results also show a daily protein goal and your pre-pregnancy BMI, which determines how much weight gain is recommended.
These figures assume a single baby and a healthy pre-pregnancy weight. The 2023 National Academies energy report adds less energy for tissue gain in the second and third trimesters when pre-pregnancy BMI is higher (+300 kcal/d underweight, +200 healthy weight, +150 overweight, −50 obese), so the calculator’s notes flag when your BMI suggests a lower or higher figure. Maintenance is estimated with the Mifflin–St Jeor equation and a standard activity multiplier rather than the National Academies’ own EER equations, so treat the total as an approximation. People carrying twins and very active people may need different amounts. Your midwife, obstetrician or a registered dietitian can tailor the numbers to you, and weight gain over time is the best check that intake is right.
With the default inputs, the daily calories is 2,204 kcal. Change any value above to recalculate instantly.
How to use the pregnancy & breastfeeding calorie calculator
- 1Choose your stage — trimester or breastfeeding period.
- 2Enter your age, height and pre-pregnancy weight (not your current weight).
- 3Pick the activity level that matches a typical week.
- 4Read your daily calorie target and the extra calories for this stage.
- 5Recheck when you move into a new trimester or your baby starts solids.
Formula and method
Your basal metabolic rate is estimated with the Mifflin–St Jeor equation for women, using pre-pregnancy weight W in kilograms, height H in centimetres and age A in years. Multiplying by an activity factor (1.2 sedentary to 1.725 very active) gives your normal maintenance calories.
The pregnancy extras follow ACOG patient guidance for people who began pregnancy at a healthy weight: +0 kcal in the first trimester, +340 kcal in the second and about +450 kcal in the third. Breastfeeding extras follow the National Academies Dietary Reference Intakes for Energy (2023): +400 kcal for exclusive breastfeeding at 0–6 months (540 kcal to make milk minus 140 kcal drawn from body stores) and +380 kcal for partial breastfeeding at 7–12 months. Protein targets use the DRI RDA of 1.1 g per kg of pre-pregnancy weight in the second half of pregnancy and while breastfeeding, and 0.8 g/kg otherwise.
- W
- Pre-pregnancy weight (kg)
- H
- Height (cm)
- A
- Age (years)
Worked examples
Second trimester, 30 years, 5 ft 5 in, 140 lb, lightly active
At 63.5 kg and 165.1 cm, BMR is about 1,356 kcal. Lightly active maintenance is 1,356 × 1.375 ≈ 1,864 kcal, and the second trimester adds 340 kcal for a target of about 2,204 kcal a day.
Third trimester, metric, moderately active
BMR = 10 × 70 + 6.25 × 170 − 5 × 34 − 161 = 1,431.5 kcal. Moderately active maintenance is 1,431.5 × 1.55 ≈ 2,219 kcal, and the third trimester adds about 450 kcal for about 2,669 kcal a day, with a protein goal of 1.1 × 70 = 77 g.
Exclusively breastfeeding a 3-month-old
At 150 lb (68.0 kg) and 5 ft 4 in (162.6 cm), BMR is about 1,395 kcal; sedentary maintenance is about 1,674 kcal. Exclusive breastfeeding in the first 6 months adds 400 kcal for roughly 2,074 kcal a day, with about 75 g of protein (1.1 g/kg). Her BMI of 25.7 is just into the overweight range, which lowers the recommended pregnancy weight gain but does not change the breastfeeding extra.
Frequently asked questions
How many extra calories do I need when pregnant?+
Most people need no extra calories in the first trimester, about 340 extra per day in the second trimester and about 450 extra per day in the third, for a single baby and a healthy starting weight.
Do I really need to eat for two?+
No. The extra energy needed is modest — roughly one healthy snack a day in the second trimester and a little more in the third. Nutrient needs such as folate, iron, iodine and protein rise more than calorie needs.
How many calories do I need while breastfeeding?+
The National Academies (2023) estimate that exclusive breastfeeding costs about 540 kcal a day, of which about 140 kcal comes from fat stored in pregnancy, so the extra intake is about 400 kcal a day for the first 6 months and about 380 kcal a day from 7 to 12 months with partial breastfeeding.
How many calories do I need if I am pregnant with twins?+
Needs are higher with twins, and recommended weight gain is higher too, but there is no single official calorie figure and advice varies between providers. This calculator assumes one baby, so ask your provider or dietitian for a twin-specific plan.
Should I use my current weight or pre-pregnancy weight?+
Use your pre-pregnancy weight. The recommended extra calories already account for the growing baby, placenta and body changes, so using your current pregnant weight would double-count them.
This tool gives general estimates and is not medical advice. Talk to a doctor or qualified professional about your health, diet or training.