Gaining weight during pregnancy is a natural, necessary, and healthy part of the journey to motherhood. It's a sign that your body is working hard to nourish and grow your baby. Rather than focusing on the number on the scale, this tool is designed to be a supportive guide. It uses established medical guidelines to provide a personalized weight gain range, helping you track your progress in a way that focuses on health, not pressure.
This calculator helps you understand the recommended targets for your unique body and pregnancy.
How to Use the Pregnancy Weight Gain Calculator
To generate your personalized tracking chart, the calculator needs a few details about you and your pregnancy:
- Your Pre-Pregnancy Details: Enter your height and your weight before you became pregnant. The tool uses this to calculate your pre-pregnancy Body Mass Index (BMI).
- Your Current Progress: Enter how many weeks pregnant you are and your current weight.
- Number of Babies: Specify if you are carrying a single baby or twins.
The calculator will then display your total recommended weight gain range for the entire pregnancy, as well as a week-by-week chart showing where your current weight falls within the healthy range for this stage.
Understanding the Official Weight Gain Guidelines
The recommendations used in this tool are based on guidelines from the Institute of Medicine (IOM) and supported by The American College of Obstetricians and Gynecologists (ACOG). They are based on your pre-pregnancy BMI category:
| Pre-Pregnancy BMI | Weight Category | Recommended Gain (Single Baby) | Recommended Gain (Twins) |
|---|---|---|---|
| Less than 18.5 | Underweight | 28-40 lbs | 50-62 lbs |
| 18.5 to 24.9 | Normal Weight | 25-35 lbs | 37-54 lbs |
| 25.0 to 29.9 | Overweight | 15-25 lbs | 31-50 lbs |
| 30.0 or greater | Obesity | 11-20 lbs | 25-42 lbs |
Where Does the Weight Go?
It can be helpful to remember that 'baby weight' is so much more than just the baby! At the end of a full-term pregnancy, the weight gain is typically distributed like this:
- Baby: 7-8 pounds
- Maternal Fat & Nutrient Stores: 6-8 pounds
- Increased Blood Volume: 3-4 pounds
- Increased Body Fluids: 2-3 pounds
- Amniotic Fluid: 2 pounds
- Uterus Growth: 2 pounds
- Breast Tissue Growth: 1-3 pounds
- Placenta: 1.5 pounds
Important Medical Notes
This tool provides a guideline, not a strict rule. Every body is different, and your weight gain pattern will be unique. This calculator is for informational purposes and should not replace advice from your healthcare provider. Your doctor or midwife will give you a personalized weight gain goal and will monitor your progress in the context of your overall health.