Pregnancy Weight Gain Calculator
Estimate a healthy weight gain schedule based on guidelines from the Institute of Medicine
Recommended weight gain during pregnancy
Understanding Pregnancy Weight Gain
Pregnancy can lead to significant changes to women’s bodies and daily routines. One such change is weight gain to ensure that there are enough nutrients for the development of the fetus as well as to store enough nutrients in preparation for breastfeeding. While weight gain during pregnancy is normal and necessary, studies have shown that certain ranges of weight gain given a specific body mass index (BMI) result in more positive outcomes for both fetus and mother.
Weight Gain Guidelines
Generally, it is recommended that pregnant women gain only 1-4 pounds during the first 3 months of pregnancy, and 1 pound per week during the remainder of the pregnancy. It is possible to achieve 1 pound per week by consuming an additional ~300 calories per day, which is roughly equivalent to eating an extra sandwich plus a glass of milk or a baked potato plus 2 ounces of meat plus an apple.
The Institute of Medicine provides a weight gain guideline based on Prepregnancy BMI:
| Prepregnancy BMI (kg/m²) | Category | Total Weight Gain Range | Total Weight Gain Range for Twins |
|---|---|---|---|
| <18.5 | Underweight | 28-40 lbs (12.7-18.1 kg) | – |
| 18.5-24.9 | Normal Weight | 25-35 lbs (11.3-15.9 kg) | 37-54 lbs (16.8-24.5 kg) |
| 25.0-29.9 | Overweight | 15-25 lbs (6.8-11.3 kg) | 31-50 lbs (14.1-22.7 kg) |
| >30.0 | Obese | 11-20 lbs (5.0-9.1 kg) | 25-42 lbs (11.3-19.1 kg) |
Where Does the Weight Go?
Weight gain during pregnancy is not just attributed to the weight of the fetus. Most of the weight gain goes to the development of tissues that allow fetal development, growth, and prepare the body for breastfeeding:
| Component | Weight |
|---|---|
| Enlarged breasts | 1-3 pounds (0.5-1.4 kg) |
| Enlarged uterus | 2 pounds (0.9 kg) |
| Placenta | 1.5 pounds (0.7 kg) |
| Amniotic fluid | 2 pounds (0.9 kg) |
| Increased blood volume | 3-4 pounds (1.4-1.8 kg) |
| Fat stores | 6-8 pounds (2.7-3.6 kg) |
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How to Use This Pregnancy Weight Gain Calculator
- Select Your Language
- Use the dropdown menu to choose your preferred language (supports 10 languages, including RTL for Arabic/Urdu).
- Choose Units (Metric or US)
- Click “Metric Units” (kg/cm) or “US Units” (lb/in) based on your preference.
- Enter Your Details
- Pregnancy Stage: Select your current trimester (1st, 2nd, or 3rd).
- Twins?: Check the box if pregnant with twins.
- Height: Enter your height in cm or inches.
- Pre-Pregnancy Weight: Your weight before pregnancy.
- Current Weight: Your weight now.
- Click “Calculate”
- Instantly view your:
- Pre-pregnancy BMI and category (e.g., “Normal Weight”).
- Recommended total weight gain range.
- Current weight gain status (green = healthy, red = consult a doctor).
- Weekly goal (~300 extra calories/day).
- Instantly view your:
- Review the Chart
- The graph shows your progress vs. the recommended range for your pregnancy stage.
- Explore Guidelines
- Scroll down for evidence-based tables on:
- Weight gain by BMI.
- Where the weight goes (breasts, placenta, etc.).
- Nutrition tips.
- Scroll down for evidence-based tables on:
Tips for Accuracy
- Measure weight consistently (e.g., morning, empty stomach).
- Update the calculator as your pregnancy progresses.
- Always consult your doctor for personalized advice.
This tool is mobile-friendly and works in all browsers. No login or downloads required!
Frequently Asked Questions (FAQ) – Pregnancy Weight Gain Calculator
1. How does this calculator determine my recommended weight gain?
It uses your pre-pregnancy BMI (based on your height and weight) and follows guidelines from the Institute of Medicine, adjusting for twins if selected.
2. Which units should I use, metric or US?
Choose whichever you’re comfortable with! The calculator automatically converts between kg/cm and lb/in.
3. Why is my current weight gain marked red?
A red alert means your gain is outside the recommended range for your trimester/BMI. Consult your doctor for personalized advice.
4. Does this work for twin pregnancies?
Yes! Check the “Pregnant with Twins” box for adjusted recommendations.
5. How often should I use this tool?
Update it every 2–4 weeks to track progress. Weight gain isn’t linear—focus on trends, not daily fluctuations.
6. Where does pregnancy weight go?
See the “Weight Distribution” table below the calculator (e.g., placenta, blood volume, fat stores).
7. Is this tool a substitute for medical advice?
No. Always consult your healthcare provider, this is for general guidance only.
8. Why isn’t my language supported?
We currently cover 10 languages (like Spanish, Arabic, Hindi). Email us to request more!
9. How accurate is the chart?
It estimates a healthy range based on averages. Your needs may vary based on health, activity, or diet.
10. Can I save my results?
Not automatically, bookmark the page or screenshot your results to share with your doctor.