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Pregnancy Weight Gain Calculator

Track your pregnancy weight gain based on ACOG guidelines

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ACOG Recommended Weight Gain by BMI

Pre-Pregnancy BMICategoryOne BabyTwins
Below 18.5Underweight28–40 lbsDiscuss with doctor
18.5 – 24.9Normal25–35 lbs37–54 lbs
25.0 – 29.9Overweight15–25 lbs31–50 lbs
30.0+Obese11–20 lbs25–42 lbs

Source: American College of Obstetricians and Gynecologists (ACOG) Committee Opinion No. 548. First trimester: 1–4 lbs total. Second and third trimesters: weekly gain based on BMI category.

Where Pregnancy Weight Goes

ComponentWeight
Baby7 – 8 lbs
Placenta1 – 2 lbs
Amniotic fluid2 lbs
Uterus growth2 lbs
Breast tissue2 lbs
Increased blood volume3 – 4 lbs
Extra fluid in tissues3 – 4 lbs
Fat stores (energy reserves)6 – 8 lbs

Typical singleton (one-baby) pregnancy weight distribution. Total: approximately 25–35 lbs.

About This Tool

The Pregnancy Weight Gain Calculator helps you track your gestational weight gain based on ACOG (American College of Obstetricians and Gynecologists) guidelines. By entering your height, pre-pregnancy weight, current weight, and gestational week, the calculator compares your actual gain to the recommended range for your pre-pregnancy BMI category.

How it works: Your pre-pregnancy BMI (Body Mass Index) determines your recommended total gain. First trimester gains are 1–4 lbs regardless of BMI. In the second and third trimesters, the weekly gain rate depends on your BMI category — about 1 lb/week for normal BMI and 0.6 lb/week for overweight BMI. The calculator supports both singleton and twin pregnancies.

For more health metrics, try our Ideal Body Weight Calculator to see your healthy weight range, or our Body Fat Percentage Calculator for body composition analysis. Explore more tools in our Health tools collection.

All processing happens entirely in your browser — no personal health data is sent to any server.

Frequently Asked Questions (FAQ)

What is the Pregnancy Weight Gain Calculator?
This calculator estimates your recommended pregnancy weight gain based on ACOG (American College of Obstetricians and Gynecologists) guidelines. By entering your height, pre-pregnancy weight, current weight, and gestational week, it determines whether your weight gain is on track.
How does ACOG determine recommended weight gain?
ACOG recommendations are based on your pre-pregnancy BMI (Body Mass Index) category. First trimester total gain is typically 1-4 lbs regardless of BMI. In the second and third trimesters, the weekly gain rate depends on your BMI category: about 1 lb/week for normal BMI, and about 0.6 lb/week for overweight BMI. Total recommended gain ranges from 28-40 lbs (underweight) to 11-20 lbs (obese).
Is this calculator accurate for twin pregnancies?
The calculator includes twin-specific recommendations based on ACOG guidelines for Normal, Overweight, and Obese BMI categories. For underweight BMI with twins, ACOG does not publish specific guidelines — please discuss weight gain goals with your healthcare provider.
Is my data processed securely?
Absolutely. All calculations happen entirely in your browser. No personal health data is sent to any server. Your calculation history is stored only in your browser's local storage and can be cleared at any time.
What if my weight gain is above or below the recommended range?
This calculator provides guidance based on population-level ACOG guidelines, but every pregnancy is unique. If your weight gain is outside the recommended range, discuss it with your healthcare provider. For related health metrics, you can also use our Body Fat Percentage Calculator or Daily Calorie Needs Calculator.
How does BMI affect pregnancy weight gain recommendations?
Your pre-pregnancy BMI category determines your recommended total weight gain. Higher BMI categories have lower recommended gain to reduce risks of gestational diabetes and delivery complications. Lower BMI categories need more gain for adequate fetal growth. For a broader fitness assessment, try our Ideal Body Weight Calculator.

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