How Much Weight Should You Gain During Pregnancy?
One of the most common questions during pregnancy is also one of the hardest to answer with a single number: how much weight should you gain during pregnancy?
There is no one pregnancy weight-gain goal that is right for everyone. Recommended weight gain during pregnancy depends largely on your body mass index, or BMI, before pregnancy and whether you are carrying one baby or multiples. Your pregnancy week also matters when you are looking at how your weight has changed so far.
That is why this calculator starts with your height and pre-pregnancy weight instead of asking you to choose a weight category yourself. It calculates your pre-pregnancy BMI, matches it with the general pregnancy weight-gain guidance for that BMI range, and then helps you understand your current progress.
The result is meant to give you a useful reference point. It is not a substitute for prenatal care, and it should never be treated like a rule that says you must gain an exact number of pounds by an exact date.
Pregnancy does not happen on a perfectly straight line, and neither does pregnancy weight gain.
Recommended Weight Gain During Pregnancy by Pre-Pregnancy BMI
For a pregnancy with one baby, general recommended total weight gain is based on your BMI before pregnancy.
If your pre-pregnancy BMI was below 18.5, the general recommended total weight gain is 28 to 40 pounds.
If your BMI was 18.5 to 24.9, the general range is 25 to 35 pounds.
If your BMI was 25.0 to 29.9, the general range is 15 to 25 pounds.
If your BMI was 30 or higher, the general range is 11 to 20 pounds.
These ranges help explain why two pregnant people of the same height may receive very different weight-gain recommendations. The starting point matters.
If you are not sure what your BMI was before pregnancy, our BMI Calculator can help you understand how BMI is calculated. This calculator also calculates your pre-pregnancy BMI automatically when you enter your height and starting weight.
Visual: Pre-Pregnancy BMI to Pregnancy Weight Gain
BMI Under 18.5
Underweight
28 to 40 lb
BMI 18.5 to 24.9
Healthy Weight
25 to 35 lb
BMI 25.0 to 29.9
Overweight
15 to 25 lb
BMI 30 or Higher
Obesity
11 to 20 lb
General total weight-gain reference ranges for a singleton pregnancy, by pre-pregnancy BMI category. Your own matching category is highlighted automatically after you use the calculator above.
Recommended total pregnancy weight gain for one baby, by pre-pregnancy BMI category
| Pre-Pregnancy BMI | Category | Recommended Total Gain |
|---|
| Below 18.5 | Underweight | 28 to 40 lb |
| 18.5 to 24.9 | Healthy Weight | 25 to 35 lb |
| 25.0 to 29.9 | Overweight | 15 to 25 lb |
| 30 or higher | Obesity | 11 to 20 lb |
What Is Normal Weight Gain During Pregnancy?
"Normal weight gain during pregnancy" does not mean one exact number.
For someone who began pregnancy in the healthy BMI range and is carrying one baby, 25 to 35 pounds is a common total reference range. Someone who started pregnancy underweight may have a higher recommended range, while someone who began pregnancy in the overweight or obesity BMI categories generally has a lower recommended total range.
The important point is that a healthy pregnancy weight-gain pattern is individualized.
A person who gains 20 pounds during pregnancy may be within the recommended range for her starting BMI, while 20 pounds may be below the usual range for someone else.
Your prenatal provider also considers factors a calculator cannot see, including your baby's growth, your health history, swelling or fluid changes, nausea and vomiting, nutrition, activity, and whether you are carrying multiples.
Typical Weight Gain During Pregnancy Is Not the Same Every Week
Many people picture pregnancy weight gain as a steady climb from week 1 through week 40.
Real pregnancies usually do not work that way.
Weight change during the first trimester is often relatively small. Some people gain several pounds. Some gain very little. Others may temporarily lose weight because of nausea, vomiting, appetite changes, or food aversions.
General guidance commonly uses an overall first-trimester gain of roughly 1.1 to 4.4 pounds as a reference.
After the first trimester, weight gain often becomes steadier as the baby, placenta, uterus, blood volume, fluid stores, and other tissues continue to grow.
For singleton pregnancies, the general second- and third-trimester reference rates differ according to pre-pregnancy BMI.
Someone who began pregnancy underweight may gain roughly 1 to 1.3 pounds per week during this stage.
Someone who began in the healthy BMI range may average roughly 0.8 to 1 pound per week.
For someone who began pregnancy overweight, the range is approximately 0.5 to 0.7 pound per week.
For someone with a pre-pregnancy BMI of 30 or higher, a general reference is approximately 0.4 to 0.6 pound per week.
These are averages and ranges, not weekly assignments.
It is possible to gain more during one week and very little during another and still have an appropriate overall pattern.
How Much Weight Should You Gain by Your Current Pregnancy Week?
This is where a pregnancy weight gain calculator by week can be especially useful.
Instead of comparing yourself only with the final 40-week goal, the calculator can use your current gestational week to show an estimated reference range for this stage of pregnancy.
During the first trimester, it is usually more helpful to look at total first-trimester change than to assign a target to each individual week.
During the second and third trimesters, the calculator can combine the general first-trimester range with the typical weekly range associated with your pre-pregnancy BMI.
For example, someone who is 24 weeks pregnant should not compare her current weight gain with a full-term 40-week target as though she has already reached the end of pregnancy.
Her result should answer a more useful question:
"How does my weight gain so far compare with the general reference for about 24 weeks?"
That is exactly what the progress visualization on this page is designed to show.
Want to confirm your exact due date, current gestational week, or trimester dates first? Use the CalculateThisWay
Pregnancy Calculator, then come back and enter your current week above.
Total Weight Gain During Pregnancy With Twins
Pregnancy weight-gain recommendations are different when you are carrying twins.
General total ranges for twin pregnancies are higher because the body is supporting two developing babies as well as additional pregnancy tissue and physiological changes.
Typical total twin-pregnancy reference ranges are approximately:
Underweight before pregnancy: 50 to 62 pounds.
Healthy BMI before pregnancy: 37 to 54 pounds.
Overweight before pregnancy: 31 to 50 pounds.
Obesity before pregnancy: 25 to 42 pounds.
Because multiple pregnancies can vary significantly, the calculator should emphasize the total reference range rather than pretend that every twin pregnancy should follow one identical week-by-week pattern.
If you are carrying triplets or more, generalized calculator guidance is not appropriate enough to give you a meaningful target. Your prenatal care team should provide an individualized recommendation.
Visual: Singleton vs. Twins Total Weight-Gain Ranges
One Baby
Healthy Weight
25 to 35 lb
Twins
Healthy Weight
37 to 54 lb
Twin-pregnancy total reference ranges are higher than singleton ranges in every BMI category, because the body is supporting two babies plus additional pregnancy tissue. Bar length reflects the midpoint of each range for easy comparison, not an exact target.
Singleton compared with twin-pregnancy total weight-gain reference ranges by pre-pregnancy BMI category
| Pre-Pregnancy BMI Category | One Baby | Twins |
|---|
| Underweight | 28 to 40 lb | 50 to 62 lb |
| Healthy Weight | 25 to 35 lb | 37 to 54 lb |
| Overweight | 15 to 25 lb | 31 to 50 lb |
| Obesity | 11 to 20 lb | 25 to 42 lb |
Where Does Pregnancy Weight Actually Go?
A common misconception is that most pregnancy weight gain is simply the baby's weight.
The baby is only one part of the total.
March of Dimes provides a useful example of where pregnancy weight can come from. A typical breakdown may include approximately 7.5 pounds for the baby, 1.5 pounds for the placenta, 2 pounds of amniotic fluid, about 4 pounds of increased blood, 3 pounds of additional body fluids, 2 pounds of breast tissue, 2 pounds from uterine growth, and roughly 6 to 8 pounds of fat, protein, and other nutrient stores.
These numbers are approximate and every pregnancy is different, but they help explain an important point:
Pregnancy weight serves many biological purposes.
Your body is building and supporting an entire pregnancy system, not simply increasing the baby's weight.
Visual: Where Pregnancy Weight Goes
Baby, about 7.5 lb
Placenta, about 1.5 lb
Amniotic fluid, about 2 lb
Uterus, about 2 lb
Breast tissue, about 2 lb
Blood, about 4 lb
Body fluids, about 3 lb
Fat, protein & nutrient stores, about 6 to 8 lb
A commonly cited example breakdown of where pregnancy weight can come from, adapted from March of Dimes. These are general examples and individual pregnancies vary.
Example breakdown of pregnancy weight gain by component
| Component | Approximate Weight |
|---|
| Baby | About 7.5 lb |
| Placenta | About 1.5 lb |
| Amniotic fluid | About 2 lb |
| Uterus | About 2 lb |
| Breast tissue | About 2 lb |
| Blood | About 4 lb |
| Body fluids | About 3 lb |
| Fat, protein and nutrient stores | About 6 to 8 lb |
What If There Is No Weight Gain During Pregnancy?
"No weight gain during pregnancy" is a search people make for many different reasons.
The meaning depends on when it happens and what else is going on.
Very little weight change early in pregnancy may not automatically mean something is wrong, particularly when nausea, vomiting, or appetite changes are present.
Later in pregnancy, weight trends are interpreted along with fetal growth and your overall health.
A calculator cannot determine whether low weight gain is safe for your specific pregnancy.
If your weight is not increasing as expected, if you are losing weight, or if you are concerned about your ability to eat enough, talk with your prenatal provider rather than trying to correct the number quickly on your own.
What Does Low Weight Gain During Pregnancy Mean?
Gaining less than a general reference range does not automatically tell you why it is happening.
Pregnancy weight can be affected by appetite, morning sickness, food access, digestive issues, activity, starting BMI, medical conditions, and many other factors.
March of Dimes notes that gaining too little weight during pregnancy can be associated with a greater chance of preterm birth and low birth weight.
That is why low pregnancy weight gain is something to discuss with your healthcare provider instead of treating it as a simple calorie problem.
Your provider can look at your weight trend together with your baby's growth.
What About Rapid Weight Gain During Pregnancy?
Pregnancy weight can sometimes increase in short bursts.
March of Dimes notes that a person may experience growth spurts where several pounds are gained within a shorter period and then the pattern levels off.
That means a single week's change should not automatically be treated as a problem.
However, if you notice rapid, unexpected, or concerning weight changes, contact your prenatal provider. Weight is only one piece of the pregnancy picture, and your healthcare team can determine whether the change is expected or needs further evaluation.
The purpose of this calculator is to show the overall pattern, not to diagnose the reason behind a sudden change.
How to Gain Weight During Pregnancy
If your healthcare provider wants you to increase your pregnancy weight gain, the goal is not simply to eat as much as possible.
Pregnancy nutrition still needs to support both you and your developing baby.
A prenatal provider or registered dietitian can help you find foods and meal patterns that provide enough energy, protein, vitamins, minerals, healthy fats, and other nutrients for your individual needs.
Do not use this calculator as a reason to aggressively increase calories on your own.
Likewise, pregnancy is generally not the time to begin a weight-loss diet unless your healthcare team has given you individualized medical guidance.
Curious about general calorie needs outside of pregnancy-specific nutrition planning? The CalculateThisWay
TDEE & Calorie Calculator can show a baseline, but your prenatal provider or a registered dietitian should guide actual pregnancy nutrition decisions.
How to Maintain Healthy Weight Gain During Pregnancy
Healthy weight gain during pregnancy is less about hitting the exact same number every week and more about watching the overall trend.
Regular prenatal visits matter because your healthcare provider is looking at much more than the number on a scale.
Your pregnancy care may include monitoring your blood pressure, baby's growth, lab work, symptoms, nutrition, and other health factors.
At home, it can be helpful to weigh yourself under similar conditions if you choose to track your weight. That might mean using the same scale and checking around the same time of day.
Avoid becoming focused on normal daily fluctuations.
Hydration, meals, clothing, digestion, and fluid retention can all change scale weight from one day to another.
The longer-term pattern is usually more meaningful.
Why Pre-Pregnancy BMI Matters
Pregnancy weight-gain guidance uses your BMI before pregnancy rather than your BMI late in pregnancy.
That distinction matters.
BMI is calculated from height and weight, but pregnancy intentionally changes body weight as the baby and supporting tissues grow. A BMI calculated from late-pregnancy weight is therefore not interpreted the same way as a pre-pregnancy BMI.
This calculator uses your pre-pregnancy height and weight to determine the starting BMI category and then matches that category with pregnancy weight-gain guidance.
If you want to understand BMI in more detail, use the CalculateThisWay BMI Calculator.
Average Weight Gain During Pregnancy Is Only a Reference
Searching for the "average weight gain during pregnancy" can be helpful, but an average does not tell you what is appropriate for your individual body.
Pregnancy recommendations are ranges for a reason.
Two people can both have healthy pregnancies while gaining different amounts of weight.
Someone expecting twins will usually gain more than someone carrying one baby.
Someone who began pregnancy underweight usually has a higher recommended total gain than someone who began pregnancy in a higher BMI category.
Your individual pregnancy should always take priority over an internet average.
Your Pregnancy Weight Gain Is a Trend, Not a Test
The best way to use this calculator is as an educational tracking tool.
Start with your pre-pregnancy measurements.
Look at the total recommended range associated with your starting BMI.
Then use your current pregnancy week and current weight, if known, to see where your progress sits within a broad reference range.
Do not treat the result as a pass-or-fail score.
Do not try to force your body to match the center of the chart every week.
Use the result to understand the numbers and to help you prepare better questions for your prenatal appointments.
March of Dimes emphasizes that gaining an appropriate amount of weight can support the health of both parent and baby and that concerns about pregnancy weight gain should be discussed with a healthcare provider.
That is the role this calculator should play:
Calculate it.
Understand it.
Then know what to discuss or consider next.
Pregnancy Weight Gain Examples
These worked examples show the math behind the calculator above. They do not replace entering your own numbers, since your own result will be personalized to your height, weight, week, and number of babies.
Example 1: Healthy BMI, One Baby
Height: 5 ft 5 in (65 in). Pre-pregnancy weight: 135 lb.
BMI = 703 × 135 ÷ 65² = 703 × 135 ÷ 4,225 = 94,905 ÷ 4,225 ≈ 22.5.
Category: Healthy Weight (BMI 18.5 to 24.9).
Recommended total gain: 25 to 35 lb.
Estimated final weight range: 135 + 25 = 160 lb to 135 + 35 = 170 lb.
Example 2: Overweight BMI, One Baby
Height: 5 ft 4 in (64 in). Pre-pregnancy weight: 160 lb.
BMI = 703 × 160 ÷ 64² = 703 × 160 ÷ 4,096 = 112,480 ÷ 4,096 ≈ 27.5.
Category: Overweight (BMI 25.0 to 29.9).
Recommended total gain: 15 to 25 lb.
Estimated final weight range: 160 + 15 = 175 lb to 160 + 25 = 185 lb.
Example 3: Healthy BMI, Twins
Height: 5 ft 6 in (66 in). Pre-pregnancy weight: 140 lb.
BMI = 703 × 140 ÷ 66² = 703 × 140 ÷ 4,356 = 98,420 ÷ 4,356 ≈ 22.6.
Category: Healthy Weight. Twins total gain: 37 to 54 lb.
Estimated final weight range: 140 + 37 = 177 lb to 140 + 54 = 194 lb.
In every case, the calculator provides general guidance. Your prenatal care provider determines individualized recommendations based on your full health picture.
Pregnancy Weight Gain Chart for One Baby
First-trimester reference for all categories: approximately 1.1 to 4.4 lb total (about 0.5 to 2.0 kg), not a per-week target.
Pregnancy Weight Gain Questions
How much weight should I gain during pregnancy?
It depends on your pre-pregnancy BMI and whether you are expecting one baby, twins, or higher-order multiples. For one baby, the general total reference ranges are 28 to 40 lb if you began underweight, 25 to 35 lb for a healthy pre-pregnancy BMI, 15 to 25 lb if you began overweight, and 11 to 20 lb for a pre-pregnancy BMI of 30 or higher. Enter your height and pre-pregnancy weight in the calculator above for your personalized range.
How much weight gain is normal during pregnancy?
Normal is a range rather than one number. Two people can both have healthy pregnancies while gaining different amounts, because the general reference ranges are built around pre-pregnancy BMI and the number of babies.
How much weight should I gain by 20 weeks pregnant?
By around 20 weeks, most of the general reference comes from combining the first-trimester range of about 1.1 to 4.4 lb with roughly seven weeks of second-trimester gain at the typical weekly rate for your BMI category. Enter week 20 in the calculator above to see the estimated reference for your own BMI category.
How much weight should I gain by 30 weeks pregnant?
By around 30 weeks you are roughly two weeks into the third trimester, so the reference combines the first-trimester range with about 17 weeks of second and third trimester gain at your BMI category's typical weekly rate. The calculator above shows this estimate automatically.
How much weight should I gain in the first trimester?
General guidance commonly uses an overall first-trimester reference of about 1.1 to 4.4 lb rather than an exact weekly figure, since early weight change varies a great deal and some people gain little or temporarily lose weight.
How much weight should I gain in the second trimester?
For a singleton pregnancy, the general second-trimester rate is roughly 0.8 to 1 lb per week for a healthy pre-pregnancy BMI, with different typical rates for underweight, overweight, and obesity BMI categories.
How much weight should I gain in the third trimester?
The typical weekly reference rate used for the second trimester generally continues into the third trimester for singleton pregnancies, though individual patterns vary and often slow somewhat near the end of pregnancy.
What is the average weight gain during pregnancy?
Averages are sometimes quoted around 25 to 35 lb for a healthy pre-pregnancy BMI with one baby, but an average does not tell you what is appropriate for your individual body. Your own recommended range depends on your pre-pregnancy BMI and whether you are carrying multiples.
What is healthy weight gain during pregnancy?
Healthy weight gain is usually described as a pattern that falls within the general reference range for your pre-pregnancy BMI category rather than one exact number, interpreted together with your prenatal provider's assessment of your health and your baby's growth.
How does pre-pregnancy BMI affect pregnancy weight gain?
Pregnancy weight-gain guidance is organized around pre-pregnancy BMI because starting body size affects how much additional weight is generally recommended. Lower starting BMI categories are generally associated with higher recommended total gain, and higher starting BMI categories are generally associated with lower recommended total gain.
How do I calculate my pre-pregnancy BMI?
BMI is calculated from height and weight. In US units, BMI equals 703 multiplied by weight in pounds, divided by height in inches squared. In metric units, BMI equals weight in kilograms divided by height in meters squared. This calculator performs that calculation automatically from your pre-pregnancy height and weight.
How much weight should I gain if I am underweight?
For one baby, the general total reference range for a pre-pregnancy BMI under 18.5 is 28 to 40 lb. For twins, the general range is approximately 50 to 62 lb.
How much weight should I gain if I am overweight?
For one baby, the general total reference range for a pre-pregnancy BMI of 25.0 to 29.9 is 15 to 25 lb. For twins, the general range is approximately 31 to 50 lb.
How much weight should I gain if my BMI is over 30?
For one baby, the general total reference range for a pre-pregnancy BMI of 30 or higher is 11 to 20 lb. For twins, the general range is approximately 25 to 42 lb.
How much weight should I gain with twins?
Twin-pregnancy total reference ranges are higher than singleton ranges because the body is supporting two babies plus additional pregnancy tissue. General ranges are approximately 50 to 62 lb if underweight, 37 to 54 lb for a healthy BMI, 31 to 50 lb if overweight, and 25 to 42 lb for a BMI of 30 or higher.
Is no weight gain during the first trimester normal?
Very little weight change, and sometimes even a small temporary decrease, is common in the first trimester, particularly with nausea, vomiting, or appetite changes. This does not automatically mean something is wrong, but ongoing concerns should be discussed with your prenatal provider.
What does low weight gain during pregnancy mean?
Gaining less than the general reference range does not by itself explain why. It can relate to appetite, nausea, food access, activity, starting BMI, and other factors, and March of Dimes notes that gaining too little weight can be associated with a greater chance of preterm birth and low birth weight, so it is worth discussing with your healthcare provider.
What does rapid weight gain during pregnancy mean?
Pregnancy weight can increase in short growth spurts, so one week's change should not automatically be treated as a problem. However, rapid, unexpected, or concerning weight changes are worth reporting to your prenatal provider, who can evaluate the full picture.
Should pregnancy weight increase every week?
Not necessarily in a perfectly even amount. Many pregnancies show more gain in some weeks and less in others while still following an appropriate overall pattern.
Can pregnancy weight gain happen in growth spurts?
Yes. March of Dimes notes that weight can increase in short bursts and then level off, which is a normal pattern rather than something that needs to be corrected week by week.
Where does pregnancy weight go?
Pregnancy weight supports much more than the baby alone. A commonly cited example breakdown includes about 7.5 lb for the baby, 1.5 lb for the placenta, 2 lb of amniotic fluid, 2 lb from uterine growth, 2 lb of breast tissue, about 4 lb of increased blood, about 3 lb of additional body fluids, and roughly 6 to 8 lb of fat, protein, and other nutrient stores.
How much does the baby account for in pregnancy weight gain?
The baby is only one part of total pregnancy weight gain, commonly estimated at around 7.5 lb in a full-term pregnancy, with the remainder coming from the placenta, amniotic fluid, blood, fluids, tissue growth, and nutrient stores.
Can I lose weight during pregnancy?
Pregnancy is generally not the time to begin an intentional weight-loss diet unless your healthcare team has given you individualized medical guidance. Some people experience temporary weight loss early in pregnancy related to nausea, but ongoing weight loss should be discussed with your provider.
What should I do if I am gaining less than the recommended amount?
Talk with your prenatal provider rather than trying to correct the number quickly on your own. They can look at your weight trend together with your baby's growth and overall health.
What should I do if I am gaining more than the recommended amount?
Discuss it with your prenatal provider instead of attempting calorie restriction or a weight-loss diet on your own. Your provider can consider your full health picture rather than one number on a chart.
Are pregnancy weight gain calculators exact?
No. A calculator provides a general educational estimate based on widely used reference ranges. It cannot see your individual health history, your baby's growth, or other factors your prenatal provider considers.
Does pregnancy weight gain vary from person to person?
Yes. Two people with healthy pregnancies and similar starting BMI can still gain somewhat different amounts of weight. The reference ranges are ranges for exactly this reason.
Is BMI still useful during pregnancy?
Pregnancy weight-gain guidance specifically uses pre-pregnancy BMI rather than a BMI calculated later in pregnancy, since pregnancy intentionally changes body weight as the baby and supporting tissues grow.
Should I use my current BMI or pre-pregnancy BMI?
Pregnancy weight-gain guidance is based on your BMI before pregnancy, not a BMI calculated from your current, later pregnancy weight. This calculator asks for pre-pregnancy height and weight for that reason.
When should I talk to my healthcare provider about pregnancy weight gain?
Anytime you have questions or concerns, including if your weight gain seems much lower or higher than the general reference range, if you notice a sudden or rapid change, or if you are unsure how to interpret your own results from this calculator.
Sources & Further Reading
This calculator provides general educational estimates based on widely used pregnancy weight-gain guidance. Individual needs vary. Your prenatal care provider can recommend a weight-gain goal based on your health, your baby's growth, and your pregnancy. This page does not diagnose pregnancy complications and does not recommend weight loss or calorie restriction during pregnancy.