Pregnancy Weight Gain Calculator
Track healthy weight gain during pregnancy
Track healthy weight gain during pregnancy based on IOM (Institute of Medicine) guidelines. Enter your pre-pregnancy weight, height, current weight, and weeks pregnant to see if you are on track.
Most common answer: A woman with a normal pre-pregnancy BMI (18.5–24.9) should gain 25–35 lbs total, with most gain in the 2nd and 3rd trimesters at about 0.8–1.0 lbs per week.
Medical Disclaimer: This calculator provides general guidelines based on IOM (Institute of Medicine) recommendations. Every pregnancy is different. Always consult your OB-GYN or midwife for personalized guidance on healthy weight gain during pregnancy.
You've gained 10.0 lbs. The recommended range at 20 weeks is 7.6 - 11.4 lbs.
Esta calculadora fornece estimativas apenas para fins informativos. Não é aconselhamento médico. Consulte um profissional de saúde antes de tomar decisões de saúde.
| BMI Category | BMI Range | Total Gain |
|---|---|---|
| Underweight | < 18.5 | 28-40 lbs |
| Normal (You) | 18.5-24.9 | 25-35 lbs |
| Overweight | 25-29.9 | 15-25 lbs |
| Obese | 30+ | 11-20 lbs |
Minimal gain expected. Focus on nutrition quality, not quantity.
Steady gain begins. Baby is growing rapidly.
Continued steady gain. Baby gains most weight in the last 8 weeks.
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Pregnancy Weight Gain Calculator
How to Use This Calculator
Enter your pre-pregnancy weight, height, current weight, and how many weeks pregnant you are. The calculator determines your BMI category and compares your actual weight gain to IOM-recommended ranges.
IOM Weight Gain Recommendations (2026)
| Pre-Pregnancy BMI | Category | Total Gain | Weekly (2nd/3rd Tri) |
|---|---|---|---|
| < 18.5 | Underweight | 28–40 lbs | 1.0–1.3 lbs/wk |
| 18.5–24.9 | Normal | 25–35 lbs | 0.8–1.0 lbs/wk |
| 25.0–29.9 | Overweight | 15–25 lbs | 0.5–0.7 lbs/wk |
| ≥ 30.0 | Obese | 11–20 lbs | 0.4–0.6 lbs/wk |
Where Does the Weight Go?
| Component | Weight at Term |
|---|---|
| Baby | 7–8 lbs |
| Placenta | 1–2 lbs |
| Amniotic fluid | 2 lbs |
| Blood volume increase | 3–4 lbs |
| Fat stores | 6–8 lbs |
Sources
- Institute of Medicine. Weight Gain During Pregnancy: Reexamining the Guidelines. 2009.
- ACOG Committee Opinion No. 548: Weight Gain During Pregnancy.
- CDC — Weight Gain During Pregnancy
Medical disclaimer: This calculator provides general IOM guidelines only. Every pregnancy is unique. Always follow your OB-GYN or midwife’s specific recommendations.
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Perguntas Frequentes
It depends on your pre-pregnancy BMI. Underweight (BMI < 18.5): 28-40 lbs. Normal weight (BMI 18.5-24.9): 25-35 lbs. Overweight (BMI 25-29.9): 15-25 lbs. Obese (BMI 30+): 11-20 lbs. These are IOM (Institute of Medicine) guidelines for singleton pregnancies. Twin pregnancies have higher recommended ranges.
Most weight gain occurs in the second and third trimesters. In the first trimester (weeks 1-13), expect only 2-4.4 lbs total. Starting in the second trimester (week 14+), steady gain of 0.5-1.3 lbs per week is normal, depending on your BMI category. Weight gain may slow slightly in the final 2-3 weeks before delivery.
Yes, mild weight loss in the first trimester is common, usually due to morning sickness and food aversions. Weight loss of 5-10 lbs is generally not concerning if you can keep fluids down. Contact your healthcare provider if you are losing more than 10 lbs, cannot keep any food or fluids down, or have severe vomiting (hyperemesis gravidarum).
Excessive weight gain increases risks of gestational diabetes, preeclampsia, cesarean delivery, large-for-gestational-age baby, and postpartum weight retention. If you are gaining faster than recommended, focus on nutrient-dense foods, maintain appropriate exercise with your doctor approval, and avoid "eating for two" (you only need 300-500 extra calories per day in the 2nd/3rd trimester).
A 30-pound pregnancy weight gain breaks down roughly as: baby (7-8 lbs), placenta (1-2 lbs), amniotic fluid (2 lbs), uterine enlargement (2 lbs), breast tissue (1-3 lbs), increased blood volume (3-4 lbs), fluid retention (2-3 lbs), and fat stores for delivery and breastfeeding (6-8 lbs). Most of this weight is lost within 6-12 months postpartum.
First trimester: no extra calories needed (eat normally). Second trimester: about 340 extra calories per day. Third trimester: about 450 extra calories per day. "Eating for two" is a myth. Quality matters more than quantity. Focus on protein, calcium, iron, folate, and omega-3 fatty acids. Your doctor may recommend prenatal vitamins.
Yes, exercise is recommended during most pregnancies. ACOG recommends 150 minutes of moderate-intensity exercise per week. Walking, swimming, prenatal yoga, and stationary cycling are safe options. Avoid contact sports, heavy lifting, and exercises lying flat on your back after the first trimester. Always get clearance from your healthcare provider.
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