Pregnancy Weight Gain Calculator
Get personalized weight gain recommendations based on your pre-pregnancy BMI, following the latest ACOG and CDC guidelines.
Your Pre-Pregnancy Stats
Personalized Guidance
Enter your pre-pregnancy stats to get ACOG-based weight gain recommendations tailored to your BMI.
Where Does Pregnancy Weight Go?
Approximate distribution at full term for a total gain of ~30 lbs
ACOG Weight Gain Guidelines
| BMI Category | Total Gain (lbs) | Total Gain (kg) | Weekly Rate (lbs) |
|---|---|---|---|
underweight BMI < 18.5 | 28–40 | 12.5–18 | 1–1.3 |
normal BMI 18.5–24.9 | 25–35 | 11.5–16 | 0.8–1 |
overweight BMI 25–29.9 | 15–25 | 7–11.5 | 0.5–0.7 |
obese BMI ≥ 30 | 11–20 | 5–9 | 0.4–0.6 |
Source: ACOG (American College of Obstetricians and Gynecologists) and CDC, 2009 IOM guidelines.
Weight Gain by Trimester
Approximate distribution for a normal-BMI pregnancy with a total gain of ~25–35 lbs
Weeks 1–13
1–4 lbs
0.5–2 kg · typical range
Minimal gain. Many women experience nausea and food aversions — some lose weight. The baby is still very small (less than 1 oz at week 12).
Weeks 14–26
12–14 lbs
5.5–6.5 kg · typical range
Steady gain of about 1 lb/week. Appetite typically returns as morning sickness fades. This is when most of the foundational growth occurs.
Weeks 27–40
8–12 lbs
3.5–5.5 kg · typical range
Baby rapidly builds fat stores. You may notice swelling from fluid retention. Gain may slow in the final weeks as the baby drops into position.
Why Pregnancy Weight Gain Matters
Gaining the right amount of weight during pregnancy supports your baby's healthy development and reduces risks for both mother and child. Too little weight gain can lead to low birth weight, preterm birth, and developmental concerns. Too much gain is associated with gestational diabetes, high blood pressure, and delivery complications.
The recommendations used in this calculator come from the 2009 Institute of Medicine (IOM) guidelines, endorsed by ACOG and the CDC. They are based on pre-pregnancy BMI because body composition influences how much additional weight is needed to support a healthy pregnancy.
Keep in mind that these are population-level guidelines — not rules. Individual needs vary based on health history, activity level, whether you're carrying multiples, and your provider's specific guidance. Use this calculator as a starting point for conversations with your midwife or OB-GYN.
Not sure how far along you are? Use our EDD calculator to find your gestational week. Or explore our pregnancy week-by-week guide to see what's happening with your baby at each stage.
Pregnancy Weight Gain — FAQs
Answers to common questions