Track your weight gain through pregnancy and see if you're on a healthy track based on IOM guidelines.
Gaining a healthy amount of weight during pregnancy is a crucial part of supporting your baby's development. This calculator uses the official guidelines from the Institute of Medicine (IOM) to provide a recommended weight gain range based on your pre-pregnancy Body Mass Index (BMI). Your BMI category (underweight, normal weight, overweight, or obese) determines your personalized recommendation for a healthy pregnancy.
It's common to wonder how the numbers on the scale add up. The weight you gain is distributed throughout your body to create the perfect environment for your baby to grow. Here is a typical breakdown for a 30-pound (13.6 kg) total weight gain:
| Baby | ~7.5 lbs (3.4 kg) |
| Placenta | ~1.5 lbs (0.7 kg) |
| Amniotic Fluid | ~2.0 lbs (0.9 kg) |
| Increased Uterus Size | ~2.0 lbs (0.9 kg) |
| Increased Breast Tissue | ~2.0 lbs (0.9 kg) |
| Increased Blood Volume | ~4.0 lbs (1.8 kg) |
| Increased Fluid Volume | ~4.0 lbs (1.8 kg) |
| Maternal Fat Stores | ~7.0 lbs (3.2 kg) |
Weight gain is not linear; it happens in stages. Understanding this pattern can help reduce anxiety about the number on the scale.
Focus on the quality of your diet, not just the quantity. The goal is to eat nutrient-dense foods that benefit both you and your baby.
Your pre-pregnancy BMI is calculated from your height and pre-pregnancy weight. The categories are: Underweight (BMI < 18.5), Normal Weight (18.5 - 24.9), Overweight (25.0 - 29.9), and Obese (BMI ≥ 30.0). This calculator determines your category automatically.
Weight gain recommendations are higher for twin pregnancies. For example, a woman with a normal BMI is recommended to gain 37-54 pounds for twins, compared to 25-35 pounds for a single baby. This calculator adjusts the recommendations if you select "Yes" for twins.
Don't panic. This calculator is a guide, not a diagnosis. Many healthy pregnancies fall slightly outside these ranges. The most important step is to discuss your weight gain, nutrition, and activity level with your healthcare provider at your regular prenatal appointments.