o Pregnancy

Pregnancy TDEE Calculator

Pregnancy TDEE rises in steps, not in one jump. This calculator applies the Institute of Medicine trimester adjustments (+0 in T1, +340 in T2, +452 in T3) on top of your pre-pregnancy maintenance. Pick your trimester below.

Pregnancy TDEE rises in steps across trimesters. Add 0 kcal per day in trimester 1, 340 kcal per day in trimester 2, and 452 kcal per day in trimester 3 to your pre-pregnancy maintenance calories. These values come from the Institute of Medicine (2002) Dietary Reference Intakes for Energy, Chapter 5.

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Your daily target

· cal/day

Enter your details and click Calculate

  • BMR · cal/day at rest
  • BMI ·  
  • Lean body mass · kg

Pick your goal

Macros at maintenance

30% protein · 40% carbs · 30% fat

Advanced metrics

Numbers are estimates. Eat at your target for 2 to 3 weeks, track weight, and adjust by ±100 cal/day if it does not match your real maintenance. See how accurate is TDEE?

Show advanced metrics 12 metrics · 7 formulas · 2D macro selector · life-stage

All metrics

Calculate above to populate the full metric table.

All 7 BMR formulas (side-by-side)

Mifflin–St Jeor · Harris–Benedict (revised) · Katch–McArdle · Cunningham · Average · Simple multiplier · Custom

TDEE across activity levels

See how much your TDEE changes between sedentary and athlete. Highlighted bar is your current selection.

Macros: 2D selector

Goal × carb-split matrix: Cut / Maintain / Bulk × Low / Moderate / High carb.

Life-stage adjustments

Luteal phase · Pregnancy (T1/T2/T3) · Breastfeeding · Perimenopause · PCOS

Direct answer

Pregnancy TDEE rises in three steps: no change in trimester 1, add 340 kcal/day in trimester 2, add 452 kcal/day in trimester 3. Both adjustments stack on top of your pre-pregnancy maintenance number.

The pregnancy TDEE calculator above defaults to Trimester 2. Change the "Life stage" dropdown to T1 or T3 for your current trimester.

Pregnancy TDEE adjustments by trimester

  • Trimester 1 (weeks 1–13): +0 kcal/day. Energy needs do not measurably change.
  • Trimester 2 (weeks 14–27): +340 kcal/day above your pre-pregnancy maintenance.
  • Trimester 3 (weeks 28–40): +452 kcal/day above your pre-pregnancy maintenance.

Twins and triplets

Multiple gestation adds calories on top of the single-baby adjustment. The IOM does not publish hard numbers, but the American College of Obstetricians and Gynecologists suggests roughly +300 kcal/day per additional fetus during T2 and T3. Discuss specifics with your OB or registered dietitian.

What to eat, not just how much

Pregnancy energy needs rise modestly, but nutrient needs rise much more. Folate, iron, choline, omega-3 DHA, iodine, and high-quality protein matter for fetal brain and tissue development. Build the +340 or +452 from nutrient-dense foods (eggs, fish, dairy, legumes, leafy greens), not from extra portions of refined carbohydrate.

Pregnancy weight-gain ranges (IOM 2009)

  • Underweight (BMI < 18.5): 28–40 lb total.
  • Healthy weight (BMI 18.5–24.9): 25–35 lb total.
  • Overweight (BMI 25–29.9): 15–25 lb total.
  • Obese (BMI ≥ 30): 11–20 lb total.

If you are tracking outside your range by mid-T2, ask your OB to review intake and activity together rather than cutting calories on your own.

What to do next

  1. Start from your pre-pregnancy maintenance calories. If you do not have a baseline, calculate it with the maintenance calorie calculator.
  2. Add the trimester adjustment above (or let the calculator do it for you).
  3. Split the daily target across 3 meals plus 2 snacks. Steady intake helps with nausea, reflux, and blood sugar stability.
  4. Re-check your number when you change trimesters or when weight-gain trajectory drifts outside the IOM range.

Sources

  • Institute of Medicine (IOM), 2002. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids, Chapter 5. National Academies Press.
  • Institute of Medicine (IOM), 2009. Weight Gain During Pregnancy: Reexamining the Guidelines. National Academies Press. Gestational weight-gain ranges by pre-pregnancy BMI.
  • American College of Obstetricians and Gynecologists. Multiple gestation calorie guidance. Discuss individual targets with your OB or registered dietitian.

Related calculators

Frequently asked questions

Why are there no extra calories in trimester 1?
The IOM 2002 report (Chapter 5) found that total energy expenditure does not change measurably in the first 12 weeks. The fetus is roughly 1 ounce at the end of T1, and maternal tissue expansion has barely begun. Eating at your pre-pregnancy maintenance during T1 is appropriate.
I have morning sickness and cannot eat much. What should I do?
Common, and rarely harmful in T1. The fetus draws on your reserves during this window. Focus on whatever you can keep down: toast, ginger tea, broth, crackers, cold smoothies. Call your OB if you cannot hold liquids, lose more than 5% of body weight, or notice dark urine. That picture suggests hyperemesis gravidarum and needs medical management.
Can I lose weight during pregnancy?
Generally not advised. Even women with a higher starting BMI should not actively cut calories during pregnancy. Aim for steady gains within the IOM 2009 weight-gain ranges (11–40 lb total depending on starting BMI). Ask your OB for an individualized target.
Do I need to eat for two?
No. The phrase predates the IOM data and overshoots by 600+ kcal per day. Even in T3 the additional need is +452 kcal/day, roughly one extra snack plus a slightly larger dinner. Doubling intake routinely produces gestational weight gain above the recommended range and raises risk of gestational diabetes and macrosomia.
Should I cut carbs or follow keto during pregnancy?
No. The fetal brain runs on glucose, and ketogenic diets in pregnancy are not well studied for safety. ACOG and most maternal-fetal medicine guidelines recommend a balanced approach with at least 175 g of carbohydrate per day. If you have gestational diabetes, follow the carb-distribution plan your provider prescribes rather than self-prescribing keto.