Pregnancy Weight Gain Calculator
Calculate your recommended pregnancy weight gain based on IOM guidelines. Enter height, pre-pregnancy weight, and week to see if you are on track. Free online health tool.
About This Calculator
The Pregnancy Weight Gain Calculator helps expectant mothers track their weight gain throughout pregnancy based on the Institute of Medicine (IOM) guidelines. By entering your height, pre-pregnancy weight, and current gestational week, you can determine whether your weight gain falls within the recommended range for your BMI category.
The calculator uses your pre-pregnancy BMI to determine which of four categories — underweight, normal weight, overweight, or obese — applies to you. Based on IOM guidelines, it then calculates the minimum and maximum recommended weight gain for your specific week, the total recommended gain by week 40, and the ideal weekly weight gain rate for your second and third trimesters. You can optionally enter your current weight to compare your actual progress against these recommendations.
Regional Notes
India: The IOM guidelines are widely referenced by obstetricians across India. The Indian Council of Medical Research (ICMR) recommends similar weight gain targets, though regional variations in maternal nutrition may affect individual recommendations. Most Indian women with normal pre-pregnancy BMI are advised to gain 10-14 kg during pregnancy.
US: The IOM guidelines are the standard of care for prenatal weight management in the United States. The American College of Obstetricians and Gynecologists (ACOG) endorses these recommendations and advises monitoring weight at each prenatal visit.
UK: The Royal College of Obstetricians and Gynaecologists (RCOG) and the National Institute for Health and Care Excellence (NICE) recommend using the IOM guidelines for weight management during pregnancy. UK practitioners also emphasize healthy eating and moderate physical activity.
Frequently Asked Questions
How much weight should I gain during pregnancy?
Weight gain during pregnancy depends on your pre-pregnancy BMI. Underweight women (BMI under 18.5) should gain 28-40 lbs (12.5-18 kg), normal weight (BMI 18.5-24.9) should gain 25-35 lbs (11.5-16 kg), overweight (BMI 25-29.9) should gain 15-25 lbs (7-11.5 kg), and obese women (BMI 30 or higher) should gain 11-20 lbs (5-9 kg), according to the Institute of Medicine guidelines.
How does the pregnancy weight gain calculator work?
Enter your height, pre-pregnancy weight, and current gestational week. The calculator computes your pre-pregnancy BMI, determines your BMI category, and provides the recommended weight gain range for your specific week based on the Institute of Medicine (IOM) guidelines. You can optionally enter your current weight to see how your actual gain compares to the recommended range.
When do you start gaining weight in pregnancy?
You start gaining weight from the beginning of pregnancy, but the most noticeable gain happens in the second trimester (weeks 13-28). During the first trimester, you typically gain only 1-4.5 lbs (0.5-2 kg) total as the baby is still tiny and morning sickness may limit weight gain.
What is the recommended weekly weight gain in the second and third trimesters?
The Institute of Medicine recommends the following weekly weight gain for the second and third trimesters: Underweight women 0.44-0.58 lbs/week (0.20-0.26 kg/week), Normal weight women 0.35-0.50 lbs/week (0.16-0.23 kg/week), Overweight women 0.23-0.33 lbs/week (0.10-0.15 kg/week), and Obese women 0.17-0.27 lbs/week (0.08-0.12 kg/week).
What should I do if I gain too much or too little weight during pregnancy?
If your weight gain deviates significantly from the recommended range, consult your healthcare provider. Gaining too much weight increases the risk of gestational diabetes, preeclampsia, cesarean delivery, and fetal macrosomia. Gaining too little weight increases the risk of preterm birth and low birth weight. In the UK and India, the same IOM guidelines are widely referenced, though your doctor may provide personalized recommendations.
Do I need to eat for two during pregnancy?
No, you do not need to eat for two. Most pregnant women only need an additional 300-350 calories per day during the second and third trimesters. Focus on nutrient-dense foods including fruits, vegetables, lean proteins, whole grains, and dairy. Take folic acid supplements as recommended by your doctor.
How often should I weigh myself during pregnancy?
It is recommended to weigh yourself once a week at the same time of day, wearing similar clothing, and using the same scale. Daily weigh-ins can be misleading due to normal fluid fluctuations. Your healthcare provider will also track your weight at each prenatal visit.
Does the recommended weight gain differ for twin pregnancies?
Yes, twin pregnancy weight gain recommendations are higher. For normal BMI women carrying twins, the recommended gain is 37-54 lbs (16.8-24.5 kg). Use our dedicated Twin Pregnancy Weight Gain Calculator for accurate twin pregnancy recommendations.