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Pregnancy Calorie Needs

Estimate your daily calorie requirements during each trimester — based on IOM recommendations.

18–50 years

Weight before pregnancy

Recommended extra calories by trimester

Values for singleton pregnancy (IOM 2002/2005).

TrimesterAdditional kcal/day
1st trimester (weeks 1–13)+0
2nd trimester (weeks 14–27)+340 kcal
3rd trimester (weeks 28–40)+452 kcal

How it works

The calculator first estimates your pre-pregnancy need with the IOM EER formula: EER = 354 − 6.91·age + PA·(9.36·weight + 726·height). It then adds the pregnancy supplement: 0 kcal in T1, +340 kcal in T2, +452 kcal in T3. For twin pregnancies, an additional +300 kcal/day is added in T2 and T3.

This is a population-based estimate. Individual needs vary with weight gain, metabolism, multiples or comorbidities. Always consult your midwife or doctor.

Frequently Asked Questions

How many extra calories do I need during pregnancy?+
Per IOM: 0 kcal in the 1st trimester, +340 kcal/day in the 2nd, and +452 kcal/day in the 3rd. Twin pregnancies add another +300 kcal/day starting in T2.
Do I really need no extra calories in T1?+
Energetically, the increase in the first trimester is essentially zero. What matters more is nutrient density — folate, iodine, iron and overall food quality.
What does 'eating for two' really mean?+
It's a myth. The extra need maxes out at about one snack (300–450 kcal). Food quality matters more than quantity.
Which formula does the calculator use?+
The IOM EER formula for adult women (DRI 2002/2005), combined with the trimester-specific energy supplement.
What counts as 'active'?+
Active means 3–5 sessions per week of moderate activity (brisk walking, swimming, yoga). 'Very active' covers competitive sport — rarely recommended during pregnancy.
Should I lose weight if I start pregnancy overweight?+
Active weight loss is not recommended. Aim for the lower end of the IOM weight-gain ranges (5–9 kg in obesity). Always coordinate with your doctor or midwife.

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Background

Pregnancy Calorie Needs: How Many Calories per Trimester?

8 min