Pregnancy Weight Gain Calculator
Track your healthy weight progression week-by-week during pregnancy. Customized based on your pre-pregnancy BMI and official Institute of Medicine clinical targets.
Enter Your Details
Adjust parameters to compute your week-specific target
Pre-Pregnancy BMI
22.5
Target Total Weight Gain (Full Term)
25.0 – 35.0 lbs
Target Range (Week 16)
5.0 – 9.0 lbs
Your Current Gain
+7.0 lbs
You are gaining weight right within the healthy recommended guideline for your current stage of pregnancy. Continue eating balanced meals!
Where Does Pregnancy Weight Actually Go?
Weight gain in pregnancy is much more than just body fat. Here is how an average 30 lbs (13.6 kg) weight gain is distributed by full term:
Baby's Weight
7.5 lbs (3.4 kg)
Average full-term birth weight of your growing infant.
Blood Volume & Fluids
8.0 lbs (3.6 kg)
Expanded blood volume (+4 lbs) and extra bodily fluids (+4 lbs).
Uterus & Placenta
3.5 lbs (1.6 kg)
Uterine muscle enlargement (+2 lbs) and the placenta (+1.5 lbs).
Fat Stores & Breasts
11.0 lbs (5.0 kg)
Maternal nutrient fat stores for delivery/lactation (+7 lbs) & breast tissue (+4 lbs).
Trimester-by-Trimester Expectations
How weight gain typically unfolds across your 40 weeks of gestation.
First Trimester
Weeks 1 – 12
Your baby is still tiny. Most women gain a total of 1 to 5 lbs (0.5 – 2.3 kg) overall during these first 12 weeks. Some women may even lose weight temporarily due to morning sickness.
Second Trimester
Weeks 13 – 27
Growth accelerates rapidly. Target a steady rate of approximately 1 lb (0.45 kg) per week if you started at a normal BMI (or ~0.5 lb/week for overweight/obese ranges).
Third Trimester
Weeks 28 – 40
Baby gains weight quickly now. Maintain ~1 lb per week through week 36, after which weight gain may plateau or slightly decrease leading up to delivery.
Healthy Principles for Pregnancy Weight Gain
Remember that pregnancy is not a time to go on a weight-loss diet. Calorie quality matters far more than just raw quantity. Aim for steady nutrient density.
Prioritize Nutrient-Dense Whole Foods
Focus on lean proteins, complex carbohydrates, avocados, nuts, leafy greens, and calcium-rich dairy.
Stay Active with Safe Exercises
Low-impact activities like prenatal yoga, swimming, and daily walking help maintain muscle tone and energy.
Hydrate Adequately
Aim for 8 to 10 glasses of water daily to support increased blood volume and amniotic fluid levels.
Medical Disclaimer
This calculator provides estimated guidance based on standardized Institute of Medicine (IOM) and American College of Obstetricians and Gynecologists (ACOG) guidelines.
Every pregnancy is unique. Factors such as pre-existing medical conditions, fluid retention, or carrying multiple babies require individual medical supervision. Always consult your OB/GYN or certified midwife regarding your specific weight targets.