Pregnancy weight Gain CalculatorĀ 

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During pregnancy, you may experience body changes where weight gain is the most important. Pregnancy lasts 40 weeks from the last menstrual period or 38 weeks from fertilization. It is divided into three trimesters

  • 1st trimester – first 12 weeks
  • 2nd trimester – from 13th till 28th week
  • 3rd trimester – from 29th week till childbirth

Pregnant women can feel changes caused to their bodies, as they fear stretch marks, urinary infections, and pain and going through labor. Not only have these some more changes occurred, which include:

  • specific breast changes,
  • significant changes in hormone regulation,
  • the arterial pressure lowers,
  • cardiac output increases by 30-50%,
  • heart rate increases by 25%,
  • blood volume increases by 45%.

All these above changes may occur due to three major reasons,

  • To enable appropriate growth for the baby
  • To prepare for the labor
  • To prepare for breastfeeding after childbirth

Pregnancy Weight Gain Calculator

How much weight can you gain during pregnancy?

In pregnancy, the ideal weight is different than in non-pregnant women. Pregnancy weight depends on two main factors: pre-pregnancy BMI and the type of pregnancy, singleton to twin.

  • If you are underweight with a BMI below 18.5, you should gain between 28 and 40 pounds during pregnancy.
  • If your normal BMI ranges from 18.5 to 24.9, you should gain 25 and 35 pounds during pregnancy.
  • If you are obese before pregnancy with a BMI of over 30, you should gain 11 and 20 pounds.

Pregnant women can gain 3-4 pounds in the first trimester. Most of the weight gain is at the time of the second trimester. In the third trimester, they keep gaining weight, and it slows down by the ninth month.

BMI chart for singleton pregnancy weight gain

Pre-pregnancy BMI – Category – Recommended weight gain

< 18.5 – underweight – 28-40lb

18.5 – 24.9 – Normal – 24–35 lb

25-29.9 – overweight – 15-25lb

>30 - obese – 11-20lb

BMI chart for twin pregnancy weight gain

Pre-pregnancy BMI – Category – Recommended weight gain

18.5-24.9 – Normal – 28-40lb

18.5-24.9 - Normal – 37-54lb

25-29.9 - overweight – 31-50lb

>30 – obese – 25-42lb

What is a pregnancy weight calculator?

The pregnancy weight calculator is a handy tool that estimates pregnancy women's weight. It determines the weight gain week by week. These values are approximate. Using this calculator, pregnant women will learn about different changes to a pregnant body.

Most weight gain goes to the development of tissues that allow fatal development and growth and prepare the body for breastfeeding. The weight gain distributions are listed below:

  • Enlarged breasts = 1-3 pounds
  • Enlarged uterus = 2 pounds
  • Placenta = 1.5 pounds
  • Amniotic fluid = 2 pounds
  • Increased blood volume = 3-4 pounds
  • Increased fluid volume = 2-3 pounds
  • Fat stores = 6-8 pounds

How to use the pregnancy weight calculator?

The steps below will show you how to calculate pregnancy weight using this calculator:

  • Enter your height and pre-pregnancy weight in boxes.
  • The pregnancy weight gain calculator will determine your pre-pregnancy BMI.
  • Choose the week of pregnancy.
  • The pregnancy weight gain calculator determines the minimum and maximum recommended weight gain since the beginning of pregnancy.
  • All these values are approved by the Institute of Medicine of the National Academies.

How to gain appropriate weight gain during pregnancy?

During pregnancy, women are hungrier than usual. Pregnant women must take plenty of fruits and vegetables as it provides more vitamins and minerals. It also helps in digestion and prevents constipation. Eat protein-rich foods like beans, fish, meat, and eggs daily to maintain good health. Avoid eating raw meat, which is the main source of infection.

Ideal weight gain distribution

At the time of pregnancy, women cannot follow the ideal weight gain distribution. There might be worrying signals:

  • Gaining more than three pounds in one week of the second trimester
  • Gaining more than two pounds in one week of the third trimester
  • Gaining no weight at all for more than two weeks in a row during 4-8 months

What to eat during pregnancy?

Eating healthy during pregnancy applies to vegetables, fruits, whole grains, lean proteins, and healthy fats. Some of the nutrients will be helpful for the growth and development of a healthy baby. Some of them are discussed below:

Folate and folic acid

Folate protects neural tube defects and potential brain and spinal cord abnormalities. It also decreases the risk of a premature baby.

  • Folic acid is the synthetic form of folate, a B vitamin that can be consumed as a supplement.
  • Folate and folic acid can help to prevent congenital disabilities.


Calcium is necessary to function in your body which helps to support strong bones and teeth. Calcium can be found in dairy products like milk, yogurt, and cheese.

Vitamin D

Vitamin D helps to promote strong bones and their strength. It is found in fortified milk, fish, orange juice, and eggs.


Protein is essential to maintain own health. It is highly important for the growth of the baby throughout pregnancy.


Pregnant women can consume double the amount of iron because it is essential for the body to produce more blood to supply oxygen to the baby. The mother is with lacks of iron, and they suffer from iron deficiency anemia, fatigue, and also increased risk of a premature baby.

During a singleton pregnancy, recommended weight gain varies depending on the pre-pregnancy BMI category. Here is a chart indicating the categories and corresponding recommended weight gain:

- Pre-pregnancy BMI < 18.5 (underweight): 28-40 lb

- Pre-pregnancy BMI 18.5-24.9 (normal weight): 24-35 lb

- Pre-pregnancy BMI 25-29.9 (overweight): 15-25 lb

- Pre-pregnancy BMI >30 (obese): 11-20 lb

For twin pregnancies, the recommended weight gain is as follows:

- Pre-pregnancy BMI 18.5-24.9 (normal weight): 28-40 lb

- Pre-pregnancy BMI 18.5-24.9 (normal weight): 37-54 lb

- Pre-pregnancy BMI 25-29.9 (overweight): 31-50 lb

- Pre-pregnancy BMI >30 (obese): 25-42 lb

A pregnancy weight calculator is useful for estimating weight gain during pregnancy. It estimates weekly weight gain, considering factors such as height and pre-pregnancy weight. The calculator provides approximate values and helps pregnant women understand their bodies' changes during pregnancy.

Weight gain during pregnancy is primarily attributed to developing tissues required for fetal growth, preparing the body for breastfeeding, and other factors. The distribution of weight gain is as follows:

- Enlarged breasts: 1-3 pounds

- Enlarged uterus: 2 pounds

- Placenta: 1.5 pounds

- Amniotic fluid: 2 pounds

- Increased blood volume: 3-4 pounds

- Increased fluid volume: 2-3 pounds

- Fat stores: 6-8 pounds

To use a pregnancy weight calculator, follow these steps:

  1. Enter your height and pre-pregnancy weight in the designated boxes.
  2. The calculator determines your pre-pregnancy BMI.
  3. Choose the week of pregnancy.
  4. This calculator can give you the recommended minimum and maximum weight gain during pregnancy.

The Institute of Medicine of the National Academies approves these weight gain values.

To achieve appropriate weight gain during pregnancy, it is important to follow a healthy diet. Pregnant women should consume plenty of fruits and vegetables for essential vitamins, minerals, and fibre. Protein-rich foods such as beans, fish, meat, and eggs benefit overall health.

Ideal weight gain distribution during pregnancy may vary, and certain signals should be monitored:

- If one gains more than three pounds in a week during the second trimester, it may be a cause for concern.

- Might be a concerning factor. If you weigh more than two pounds in one week during your third trimester, it may cause concern.

- Not gaining any weight for more than two consecutive weeks between months 4 and 8

During pregnancy, consuming a healthy diet of vegetables, fruits, whole grains, lean proteins, and healthy fats is important. Certain nutrients are particularly beneficial for the growth and development of a healthy baby:

  1. Folate and folic acid: This helps prevent neural tube defects and decreases the risk of premature birth.
  2. Calcium: Essential for supporting strong bones and teeth, found in dairy products.
  3. Vitamin D: Promotes bone strength and can be obtained from fortified milk, fish, orange juice, and eggs.
  4. Protein: Important for overall health and the baby's growth throughout pregnancy.
  5. Iron: Pregnant women require double the amount of iron to produce more blood and prevent iron deficiency anemia, fatigue, and the risk of premature birth.

During pregnancy, certain foods should be avoided. Raw, undercooked, or contaminated foods pose a higher risk of food poisoning due to bacteria. Additionally, excessive caffeine consumption should be avoided, as it can cross the placenta and affect the baby.To ensure healthy weight gain during pregnancy, consider the following steps:

  1. Take note of your calorie needs:

   - First trimester: No extra calories needed.

   - Second trimester: Approximately 340 additional calories per day.

   - Third trimester: Approximately 450 additional calories per day.

  1. Track your pregnancy weight gain:

   - Monitor your weight throughout the pregnancy and compare it to the recommended healthy weight gain.

  1. Limit added sugars and solid fats:

   - Control the consumption of sugary items and solid fats found in soft drinks, desserts, fried foods, fatty meals, and whole milk.

  1. Engage in physical activity:

   -Since most pregnant women can safely and profit from physical activity, aim for at least 150 minutes of moderate-intensity aerobic activity each week.

Proper prenatal care is crucial during pregnancy. Regular visits may include procedures such as medical history assessments, abdominal and vaginal examinations, blood type identification, blood pressure measurement, urinalysis, HIV and syphilis testing, vaccination, and educational sessions.

Maintaining a healthy weight throughout pregnancy is crucial for a healthy pregnancy and for the best results for both mother and the unborn child. One approach to achieve this is using a pregnant weight calculator to monitor weight growth and ensure it stays within the advised range. Pregnant women, too, need to maintain a healthy diet, exercise frequently, and receive appropriate prenatal care.

Monitoring your weight gain during pregnancy is essential for a healthy pregnancy. Use the Pregnancy Weight Gain Calculator to track your progress, ensure you stay within the recommended range, and make informed decisions about your health and your baby's well-being.


Q.When do you start gaining weight during pregnancy?

A.In pregnancy, weight gain happens in the second trimester

Q.Do I gain weight faster in the second pregnancy?

A.Weight gain in the second pregnancy is the same as the first one.

Q.How much weight should women gain at the time of pregnancy?

A.Pregnancy women gain 25 to 35 pounds during pregnancy time.

Q.What is BMI, and why is it important during pregnancy?

A.BMI is known as Body Mass Index, which is used to calculate weight; it is used at the time of pregnancy to maintain a healthy weight gain.

Q. On what base is the pregnancy weight gain calculator made?

A.The calculator is based on the 2009 Institute of Medicine recommendations for weight gain in pregnancy.