Updated on May 7th, 2026

Pregnancy Weight Gain Calculator

Created By Jehan Wadia

Your Information
Enter a valid weight
Enter a valid weight
ft
in
Enter a valid height
Select your current gestational week (1–40).

Your Pregnancy Weight Gain Results

Pre-Pregnancy BMI
25.0
Normal Weight
Recommended Total Gain
25 – 35 lbs
Your Current Weight Gain
8.0 lbs
Status at Week 20
On Track
Recommended Gain at Week 20
10.0 – 14.0 lbs
Recommended Weekly Gain (2nd/3rd Tri)
0.8 – 1.0 lbs/wk
Target Weight at Delivery
175 – 185 lbs
Remaining Recommended Gain
17 – 27 lbs
Weight Gain Progress
You've gained 8.0 lbs of your recommended 25–35 lbs
27%
0 Mid Target
Trimester Breakdown
1st Trimester (Weeks 1–13)
Recommended Gain1.1 – 4.4 lbs
Weekly Rate~0.1 – 0.3 lbs/wk
NotesMinimal gain expected
2nd Trimester (Weeks 14–27)
Recommended Gain10.5 – 14.0 lbs
Weekly Rate~0.8 – 1.0 lbs/wk
NotesSteady gain begins
3rd Trimester (Weeks 28–40)
Recommended Gain10.5 – 14.0 lbs
Weekly Rate~0.8 – 1.0 lbs/wk
NotesContinued steady gain
Weight Gain Trajectory
Week-by-Week Breakdown
Week Trimester Rec. Low Gain Rec. High Gain Rec. Low Weight Rec. High Weight Your Weight
Understanding Your Results
IOM/ACOG Guidelines

These recommendations are based on the Institute of Medicine (IOM) guidelines, endorsed by the American College of Obstetricians and Gynecologists (ACOG). They are designed to optimize outcomes for both mother and baby.

Underweight (BMI < 18.5): Recommended gain of 28–40 lbs (12.5–18 kg) for singleton pregnancies.

Normal Weight (BMI 18.5–24.9): Recommended gain of 25–35 lbs (11.5–16 kg).

Overweight (BMI 25.0–29.9): Recommended gain of 15–25 lbs (7–11.5 kg).

Obese (BMI ≥ 30.0): Recommended gain of 11–20 lbs (5–9 kg).

Important Reminders

This calculator provides general estimates only. Every pregnancy is unique. Factors such as age, activity level, medical conditions, and individual metabolism can influence appropriate weight gain.

Always consult your healthcare provider for personalized guidance on weight gain during your pregnancy.

Weight gain is not always linear — some weeks you may gain more or less than average, and that is perfectly normal.


Introduction

Gaining the right amount of weight during pregnancy is important for both you and your baby. Too little or too much weight gain can lead to health problems. The amount of weight you should gain depends on your weight before pregnancy, often measured using your Body Mass Index (BMI). Our Pregnancy Weight Gain Calculator helps you figure out how much weight is healthy to gain during each stage of your pregnancy. Just enter your pre-pregnancy weight, height, and how far along you are, and the calculator will show you a recommended weight gain range based on guidelines from the Institute of Medicine (IOM). This tool gives you a quick and easy way to track your progress and stay on a healthy path throughout your pregnancy.

How to Use Our Pregnancy Weight Gain Calculator

Enter a few details about yourself and your pregnancy below. The calculator will tell you how much weight you should gain during your pregnancy based on guidelines from health experts.

Pre-Pregnancy Weight: Enter how much you weighed before you became pregnant. You can use pounds or kilograms. This number helps figure out your starting point.

Height: Enter your height in feet and inches or centimeters. Your height is used along with your weight to calculate your BMI (Body Mass Index). If you're curious about how your height compares to predicted values, you can try our Height Calculator.

Pre-Pregnancy BMI (optional): If you already know your BMI from before pregnancy, you can enter it here. If you don't know it, the calculator will figure it out using your weight and height.

Number of Babies: Select whether you are carrying one baby or twins. Women carrying twins need to gain more weight for a healthy pregnancy.

Current Week of Pregnancy: Enter how many weeks pregnant you are right now. This helps the calculator show how much weight you should have gained so far and how much more you should expect to gain. If you're unsure of your timeline, our Due Date Calculator can help you determine where you are in your pregnancy.

Current Weight: Enter how much you weigh right now. The calculator will compare this to your recommended weight gain range and let you know if you are on track.

Understanding Pregnancy Weight Gain

When you're pregnant, gaining weight is a normal and healthy part of growing a baby. But how much weight you should gain depends on a few important factors, like your weight before pregnancy and whether you're carrying one baby or more.

How Much Weight Should You Gain?

Doctors use your pre-pregnancy BMI (Body Mass Index) to figure out a healthy weight gain range for you. If you'd like to understand your body composition in more detail, tools like the Body Fat Calculator or Ideal Body Weight Calculator can provide additional insight. Here are the general guidelines from the American College of Obstetricians and Gynecologists (ACOG):

  • Underweight (BMI under 18.5): 28 to 40 pounds
  • Normal weight (BMI 18.5 to 24.9): 25 to 35 pounds
  • Overweight (BMI 25 to 29.9): 15 to 25 pounds
  • Obese (BMI 30 or higher): 11 to 20 pounds

Where Does the Weight Go?

The weight you gain during pregnancy isn't just body fat. It includes the baby, the placenta, amniotic fluid, extra blood, a larger uterus, breast tissue, and stored energy your body needs for labor and breastfeeding. Each of these plays a role in keeping you and your baby healthy. Understanding your lean body weight before pregnancy can help put these changes into perspective.

Why Does Healthy Weight Gain Matter?

Gaining too little weight can lead to a baby born too small or too early. Gaining too much weight raises your risk for gestational diabetes, high blood pressure, and a harder delivery. Staying within the recommended range gives both you and your baby the best chance at a healthy pregnancy and birth.

When Do You Gain the Most?

Most people gain only 1 to 5 pounds during the first trimester. After that, a steady gain of about 1 pound per week during the second and third trimesters is typical for someone at a normal pre-pregnancy weight. The rate may be slightly less or more depending on your BMI category.

Nutrition During Pregnancy

Proper nutrition is essential for healthy weight gain. Understanding your daily calorie needs with a Calorie Calculator or planning your macronutrient intake using a Macro Calculator can help you fuel your body appropriately. Staying hydrated is equally important—our Water Intake Calculator can help you determine how much water you need each day, and getting enough rest is crucial as well, which is where our Sleep Calculator comes in handy. Ensuring adequate protein intake and fiber intake also supports a healthy pregnancy.

Important: Every pregnancy is different. This calculator gives you a general estimate based on well-known medical guidelines. Always talk to your doctor or midwife about the weight gain goal that's right for you.


Frequently Asked Questions

What is a Pregnancy Weight Gain Calculator?

A Pregnancy Weight Gain Calculator is a tool that tells you how much weight is healthy to gain during pregnancy. It uses your pre-pregnancy weight, height, and current week of pregnancy to give you a recommended range based on medical guidelines.

What is BMI and why does it matter for pregnancy weight gain?

BMI stands for Body Mass Index. It is a number based on your weight and height that shows if you are underweight, normal weight, overweight, or obese. Doctors use your pre-pregnancy BMI to decide how much weight you should gain during pregnancy. Different BMI categories have different recommended weight gain ranges.

Is it normal to lose weight in the first trimester?

Yes. Some women lose a small amount of weight in the first trimester because of morning sickness or nausea. This is usually not a problem. Most weight gain happens in the second and third trimesters. If you are losing a lot of weight or cannot keep food down, talk to your doctor.

How accurate is this pregnancy weight gain calculator?

This calculator gives a general estimate based on guidelines from the Institute of Medicine and ACOG. It is a helpful guide, but every pregnancy is different. Your doctor may adjust your weight gain goal based on your personal health, medical history, and how your pregnancy is going.

What happens if I gain more weight than recommended?

Gaining more weight than recommended can raise your risk for gestational diabetes, high blood pressure, a larger baby, and a harder delivery. It can also make it harder to lose the weight after birth. Talk to your doctor about safe ways to manage your weight during pregnancy.

What happens if I don't gain enough weight during pregnancy?

Not gaining enough weight can lead to a baby that is born too small or too early. It can also mean your baby is not getting enough nutrients to grow properly. If you are struggling to gain weight, your doctor can help you create a plan to eat more nutritious foods.

How much weight should I gain per week during pregnancy?

During the first trimester, most women gain only 1 to 5 pounds total. In the second and third trimesters, a gain of about 1 pound per week is typical for someone with a normal BMI. Women who are overweight or obese may gain a bit less per week, while underweight women may need to gain a bit more.

Does the recommended weight gain change for twins?

Yes. Women carrying twins need to gain more weight. For example, a woman with a normal BMI carrying twins should gain about 37 to 54 pounds, compared to 25 to 35 pounds for a single baby. The calculator adjusts its recommendations when you select twins.

Can I diet during pregnancy to control weight gain?

No. Pregnancy is not a safe time to go on a calorie-restricting diet. Your baby needs steady nutrition to grow. Instead of dieting, focus on eating healthy foods like fruits, vegetables, whole grains, lean protein, and dairy. Talk to your doctor before making any big changes to your eating habits.

Is it safe to exercise during pregnancy to manage weight?

Yes, for most women. Light to moderate exercise like walking, swimming, or prenatal yoga is safe and can help you manage weight gain. Exercise also helps with mood, sleep, and preparing your body for labor. Always check with your doctor before starting or continuing an exercise routine during pregnancy.

Why does my weight fluctuate so much during pregnancy?

Weight can go up and down during pregnancy because of water retention, how much you ate or drank, and even the time of day. This is normal. What matters most is the overall trend over weeks, not day-to-day changes. Try to weigh yourself at the same time each day for the most consistent readings.

How soon after giving birth will I lose the pregnancy weight?

You will lose some weight right away from the baby, placenta, and amniotic fluid. Most women lose the rest of the pregnancy weight over 6 to 12 months. Breastfeeding, healthy eating, and gentle exercise can help. Be patient with your body and avoid crash diets.

Should I use my current weight or pre-pregnancy weight for this calculator?

You need both. Enter your pre-pregnancy weight so the calculator can figure out your BMI and recommended weight gain range. Then enter your current weight so it can tell you if you are on track for your current week of pregnancy.


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