Pregnancy TDEE Calculator | Daily Calorie Needs by Trimester
Find out how many calories you need during pregnancy. Select your trimester to apply the correct IOM calorie addition, and choose your pre-pregnancy BMI to see your recommended total weight gain range alongside your daily calorie target.
Your Stats
Switches to Katch-McArdle for higher accuracy when body fat is known.
+340 kcal/day to support fetal growth, placenta, and expanding blood volume (IOM, 2009).
IOM (2009) recommended total pregnancy weight gain for your starting BMI category: 11.5 to 16 kg.
Enter your stats to see your pregnancy TDEE.
What Is TDEE During Pregnancy?
TDEE, or Total Daily Energy Expenditure, is the total number of calories your body burns in 24 hours. During pregnancy, TDEE increases above the pre-pregnancy baseline to support fetal growth, placenta development, blood volume expansion, breast tissue changes, and the added metabolic work of carrying an increasingly heavier load throughout the day.
The IOM (2009) trimester additions are population averages based on the measured energy cost of each stage of fetal development. The first trimester requires no additional calories because the embryo is too small to meaningfully drive calorie needs. The second and third trimesters require progressively larger additions as fetal weight gain accelerates. This calculator applies those additions on top of your standard TDEE and shows your trimester-specific daily target.
No additional calories above pre-pregnancy TDEE. Fetal growth in weeks 1 to 13 is primarily cellular differentiation. The embryo is too small to require meaningful extra energy (IOM, 2009).
+340 kcal per day from week 14 onward. This covers accelerating fetal weight gain, placenta growth, blood volume expansion, and breast tissue development.
+450 kcal per day from week 28. Fetal weight roughly doubles in the third trimester, driving the largest calorie increment of any pregnancy stage.
The IOM weight gain recommendation depends on your pre-pregnancy BMI. The panel in this calculator shows your target range automatically when you select your BMI category.
How Does This Pregnancy TDEE Calculator Work?
Three inputs convert your stats into a trimester-specific daily calorie target with an IOM-based weight gain reference range.
- BMR
- Trimester
- BMI
Calculate Your Current BMR
What Factors Influence TDEE During Pregnancy?
Six variables affect how many calories a pregnant woman actually needs beyond what the trimester addition formula predicts.
Fetal Growth Rate by Trimester
Calorie needs track fetal growth: minimal in the first trimester, rising sharply in the second, and peaking in the third. The trimester-based addition structure in this calculator matches the timing of fetal energy demands.
Pre-Pregnancy Body Weight and BMI
Women who begin pregnancy at a higher BMI are recommended to gain less total weight. This does not mean eating less than the trimester addition suggests; it means the pre-pregnancy TDEE baseline is higher and the same addition applies on top of it.
Physical Activity During Pregnancy
ACOG recommends maintaining moderate activity for most uncomplicated pregnancies. Active women in their second and third trimesters may need 200 to 400 kcal more than the IOM addition suggests to maintain training performance and appropriate weight gain rate.
Nausea and Food Aversions
First-trimester nausea can make eating to TDEE difficult. Eating smaller, more frequent meals and focusing on calorie-dense tolerated foods is more practical than hitting a specific number. The zero-addition for the first trimester means the impact on fetal growth is minimal if intake falls short temporarily.
Sleep and Fatigue
Progesterone in the first trimester and physical discomfort in the third both reduce sleep quality. Fatigue reduces NEAT (spontaneous movement), which can lower effective TDEE below the formula prediction even when activity level selection has not changed.
Multiple Pregnancy
Twin pregnancies require approximately double the IOM trimester additions from the second trimester onward. The standard formula and additions in this calculator are calibrated for singleton pregnancies. Consult your OB for twin-specific calorie guidance.
How Do You Use Your Pregnancy TDEE?
The goals during pregnancy are different from any other life stage. TDEE is the floor, not a number to create a deficit from.
Eat to Your Trimester-Adjusted TDEE
Match intake to the TDEE shown in the result panel for your trimester. This is not a number to create a deficit from; it is the target. The Maintenance Calorie Calculator can help you build a 2-week baseline before pregnancy to know your true pre-pregnancy TDEE.
Gain Weight at the IOM-Recommended Rate
For normal pre-pregnancy BMI, aim for 0.5 to 2 kg in the first trimester and 0.4 to 0.5 kg per week in the second and third. Weekly weight tracking against these benchmarks tells you whether your calorie intake matches the formula prediction or needs adjustment.
Maximize Nutrient Density, Not Just Calories
The pregnancy calorie additions are relatively small. Protein, folate, iron, calcium, DHA, and iodine all need to increase proportionally more than calories do. Use the Macro Calculator to set protein targets and focus each added calorie on nutrient-dense foods.
What Are the Best Nutrition Tips During Pregnancy?
Six habits that support a healthy pregnancy weight gain trajectory and nutrient adequacy across all three trimesters.
- 1
Do not eat for two in the first trimester
The first-trimester addition is zero. Eating significantly above your pre-pregnancy TDEE during this window adds fat, not fetal tissue. Focus on food quality and folate adequacy rather than increasing total intake.
- 2
Eat 1.1 g of protein per kilogram of body weight at minimum
Protein needs rise to approximately 1.1 g per kilogram per day during pregnancy (IOM). In practice, eating 1.3 to 1.5 g per kilogram gives a comfortable margin and supports both fetal tissue synthesis and maternal muscle maintenance.
- 3
Take a prenatal supplement from before conception through weaning
No diet fully covers every pregnancy nutrient need at the required levels. Folate in the first trimester, iodine throughout, and DHA for fetal brain development are the three nutrients most likely to be insufficient from food alone.
- 4
Track weekly weight gain against your IOM target
For normal pre-pregnancy BMI, the target is roughly 0.4 to 0.5 kg per week in the second and third trimesters. Gaining faster than this consistently suggests calories are above TDEE. Gaining slower or losing weight in the second or third trimester needs prompt discussion with your OB.
- 5
Stay active throughout an uncomplicated pregnancy
ACOG recommends 150 minutes of moderate activity per week for most pregnant women. Exercise supports appropriate gestational weight gain, reduces gestational diabetes risk, and improves sleep quality. Adjust your activity-level selection in this calculator to reflect your actual training load.
- 6
Update the calculator each trimester
Your weight, activity level, and calorie addition all change across pregnancy. Recalculating at the start of each trimester, or any time your weight changes by 5 kg or more, keeps your daily target aligned with your actual needs.
Frequently Asked Questions
Quick answers to the questions people ask most.
The Institute of Medicine (IOM, 2009) guidelines set the additions at zero extra calories in the first trimester, +340 kcal per day in the second trimester, and +450 kcal per day in the third trimester. These numbers assume a singleton pregnancy with normal pre-pregnancy body weight. Women carrying twins need approximately double these additions from the second trimester onward.
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