Pregnancy · Nutrition

Pregnancy Calorie Calculator

Find your daily calorie target during pregnancy. Combines the Mifflin-St Jeor BMR equation with your activity level and the standard trimester energy increments from the Institute of Medicine.

Last reviewed 22 May 2026

Pregnancy calorie needs

Daily calorie target by trimester

Activity level

Trimester

Enter your weight, height and age to see your daily calorie target.

How to use this calculator

Enter your pre-pregnancy weight, height, and age, then pick your usual activity level and current trimester. The calculator computes your basal metabolic rate (BMR), multiplies by an activity factor to get your total daily energy expenditure (TDEE), and adds the trimester-specific energy increment.

Background — the math

The Mifflin-St Jeor equation is the most accurate widely used BMR formula for non-pregnant adults. For women it is 10 × weight (kg) + 6.25 × height (cm) − 5 × age (yr) − 161.

BMR is the energy you would burn at complete rest. TDEE multiplies BMR by an activity factor that captures everyday movement and exercise:

  • Sedentary (1.20): desk job, little to no exercise.
  • Light (1.375): light exercise 1–3 days / week.
  • Moderate (1.55): moderate exercise 3–5 days / week.
  • Very active (1.725): hard exercise 6–7 days / week or physical job.

Pregnancy adds a fixed daily energy increment on top of TDEE: 0 kcal in the first trimester, +340 kcal in the second, +452 kcal in the third (Institute of Medicine, 2002 Dietary Reference Intakes for energy).

Interpreting your result

The calorie target is a range guide, not a daily quota. Real appetite, nausea, fatigue and weight-gain trajectory matter more than hitting a number. If your weight gain is following the IOM range for your pre-pregnancy BMI, you are very likely eating enough.

Macro split: protein needs rise in pregnancy — the calculator suggests around 22 % of calories from protein (about 70–100 g/day for most singleton pregnancies), with the rest split roughly 50 % carbs and 28 % fats. Hit the protein target reliably; the rest is flexible.

Limitations

  • Designed for singleton pregnancies. Twins / multiples need more energy and protein.
  • Activity factor is a rough self-rating. Real energy expenditure can vary by ±10 %.
  • Underlying medical conditions (gestational diabetes, hyperemesis, thyroid disease) can shift needs significantly — use this calculator alongside, not instead of, advice from your obstetric team.
  • Calorie counting can be unhelpful for people with a history of disordered eating. If that’s you, focus on regular meals, snacks, and the protein target rather than a daily number.

Sources

  • Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press, 2002 / 2005.
  • Mifflin MD, St Jeor ST, Hill LA, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51:241-7.
  • American College of Obstetricians and Gynecologists (ACOG). Nutrition during pregnancy (FAQ).
  • Academy of Nutrition and Dietetics. Position paper: Nutrition and lifestyle for a healthy pregnancy outcome. J Acad Nutr Diet 2014;114:1099-103.

Frequently asked questions

Is pregnancy really not 'eating for two'?
Not in calorie terms. First-trimester energy needs are unchanged. The second trimester adds about 340 kcal/day (≈ a yogurt and a banana with peanut butter); the third trimester adds about 452 kcal/day (≈ a small extra meal). What does roughly double is the need for several specific nutrients — folate, iron, choline, iodine, calcium — which is why food quality matters more than food quantity.
Which formula does this calculator use?
Basal metabolic rate (BMR) is computed using Mifflin-St Jeor — the most accurate widely used equation for adults. BMR is multiplied by a Harris-Benedict-style activity factor (1.20 sedentary, 1.375 light, 1.55 moderate, 1.725 very active) to get total daily energy expenditure (TDEE). The trimester adjustment uses the IOM/RDA 2002 increments of 340 and 452 kcal.
Should I use my pre-pregnancy weight or current weight?
Use pre-pregnancy weight. The IOM increments were derived on top of pre-pregnancy energy needs; double-counting pregnancy weight gain in the BMR would overshoot the target.
What about twins or multiples?
Estimated extra energy needs for twins are roughly 600 kcal/day above pre-pregnancy from the start of T2, with higher protein requirements as well. This calculator targets singleton pregnancies; if you're carrying multiples, work directly with your obstetric team or a registered dietitian.
Why does my appetite not match the calculator?
Appetite varies a lot in pregnancy. Early nausea can mean you eat well below target; later in pregnancy reduced stomach capacity can split intake into many small meals. As long as your weight gain is tracking along your IOM range and your blood work looks normal, you don't need to hit a number every day.

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