Pregnancy Weight Gain Calculator
Use this pregnancy weight gain calculator to estimate recommended weight gain from your pre-pregnancy BMI and current week.
Kimberly Langdon, MD
Kimberly Langdon, MD, is a retired, board-certified obstetrician/gynecologist with 19 years of clinical practice, trained at The Ohio State University.
Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How Pregnancy Weight Gain Targets Are Calculated
There’s no single healthy weight gain number for pregnancy, it depends entirely on where you started. This calculator uses your pre-pregnancy BMI to place you in one of four categories, each with its own recommended total gain and expected pace through the second and third trimesters.
What This Calculator Measures
This gives you a recommended total gain range and an estimate of where you should be by your current week, not a verdict on whether your actual gain so far is right or wrong. Individual pregnancies vary.
Step 1: Determine Your Pre-Pregnancy BMI Category
We calculate your BMI from your pre-pregnancy height and weight, then place it into one of four categories¹.
Pre-Pregnancy BMI | Category |
Below 18.5 | Underweight |
18.5 to 24.9 | Normal Weight |
25.0 to 29.9 | Overweight |
30.0 and above | Obesity |
Step 2: Apply the Recommended Gain Range for Your Category
Each category carries its own total gain range for a singleton pregnancy, endorsed by ACOG¹ based on Institute of Medicine guidelines².
Category | Recommended Total Gain |
Underweight (BMI below 18.5) | 28 to 40 lb (12.5 to 18 kg) |
Normal weight (BMI 18.5 to 24.9) | 25 to 35 lb (11.5 to 16 kg) |
Overweight (BMI 25 to 29.9) | 15 to 25 lb (7 to 11.5 kg) |
Obesity (BMI 30 and above) | 11 to 20 lb (5 to 9 kg) |
Step 3: Track Weekly Gain in the Second and Third Trimester
Most weight gain happens after the first trimester, which typically accounts for only 1 to 4.5 lb of the total². We apply a steady weekly gain rate for your BMI category to estimate your expected progress at your current week, assuming a singleton pregnancy.
How This Calculator Computes Your Result
Enter your pre-pregnancy height, weight, and current week of pregnancy above. We calculate your pre-pregnancy BMI, match it to a category, and estimate both your total recommended range and your expected progress at your current week.
A Note on Accuracy
These ranges are general guidance for a singleton pregnancy. Your OB-GYN or midwife may recommend a different target based on your health history, multiples, or pre-existing conditions.
Frequently Asked Questions
How much weight should I gain during pregnancy?
It depends on your pre-pregnancy BMI. Most guidelines recommend 25 to 35 lb for a normal BMI, with higher ranges for underweight and lower ranges for overweight or obese pre-pregnancy BMI¹.
Is this calculator accurate for twin pregnancies?
No. This calculator is designed for singleton pregnancies. Twin and multiple pregnancies have separate, higher recommended weight gain ranges.
What if I'm gaining weight faster or slower than recommended?
Some variation week to week is normal. If your gain is consistently far outside the recommended range, talk to your OB-GYN or midwife about your individual plan.
Does this calculator account for the first trimester?
Yes. First trimester gain is typically small, about 1 to 4.5 lb total², with most of the recommended gain occurring during the second and third trimesters.
Sources
Weight Gain During Pregnancy, ACOG Committee Opinion No. 548, 2013
Weight Gain During Pregnancy: Reexamining the Guidelines, Institute of Medicine & National Research Council, 2009
Pregnancy Weight Gain Calculator
Use this pregnancy weight gain calculator to estimate recommended weight gain from your pre-pregnancy BMI and current week.
Kimberly Langdon, MD
Kimberly Langdon, MD, is a retired, board-certified obstetrician/gynecologist with 19 years of clinical practice, trained at The Ohio State University.
Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How Pregnancy Weight Gain Targets Are Calculated
There’s no single healthy weight gain number for pregnancy, it depends entirely on where you started. This calculator uses your pre-pregnancy BMI to place you in one of four categories, each with its own recommended total gain and expected pace through the second and third trimesters.
What This Calculator Measures
This gives you a recommended total gain range and an estimate of where you should be by your current week, not a verdict on whether your actual gain so far is right or wrong. Individual pregnancies vary.
Step 1: Determine Your Pre-Pregnancy BMI Category
We calculate your BMI from your pre-pregnancy height and weight, then place it into one of four categories¹.
Pre-Pregnancy BMI | Category |
Below 18.5 | Underweight |
18.5 to 24.9 | Normal Weight |
25.0 to 29.9 | Overweight |
30.0 and above | Obesity |
Step 2: Apply the Recommended Gain Range for Your Category
Each category carries its own total gain range for a singleton pregnancy, endorsed by ACOG¹ based on Institute of Medicine guidelines².
Category | Recommended Total Gain |
Underweight (BMI below 18.5) | 28 to 40 lb (12.5 to 18 kg) |
Normal weight (BMI 18.5 to 24.9) | 25 to 35 lb (11.5 to 16 kg) |
Overweight (BMI 25 to 29.9) | 15 to 25 lb (7 to 11.5 kg) |
Obesity (BMI 30 and above) | 11 to 20 lb (5 to 9 kg) |
Step 3: Track Weekly Gain in the Second and Third Trimester
Most weight gain happens after the first trimester, which typically accounts for only 1 to 4.5 lb of the total². We apply a steady weekly gain rate for your BMI category to estimate your expected progress at your current week, assuming a singleton pregnancy.
How This Calculator Computes Your Result
Enter your pre-pregnancy height, weight, and current week of pregnancy above. We calculate your pre-pregnancy BMI, match it to a category, and estimate both your total recommended range and your expected progress at your current week.
A Note on Accuracy
These ranges are general guidance for a singleton pregnancy. Your OB-GYN or midwife may recommend a different target based on your health history, multiples, or pre-existing conditions.
Frequently Asked Questions
How much weight should I gain during pregnancy?
It depends on your pre-pregnancy BMI. Most guidelines recommend 25 to 35 lb for a normal BMI, with higher ranges for underweight and lower ranges for overweight or obese pre-pregnancy BMI¹.
Is this calculator accurate for twin pregnancies?
No. This calculator is designed for singleton pregnancies. Twin and multiple pregnancies have separate, higher recommended weight gain ranges.
What if I'm gaining weight faster or slower than recommended?
Some variation week to week is normal. If your gain is consistently far outside the recommended range, talk to your OB-GYN or midwife about your individual plan.
Does this calculator account for the first trimester?
Yes. First trimester gain is typically small, about 1 to 4.5 lb total², with most of the recommended gain occurring during the second and third trimesters.
Sources
Weight Gain During Pregnancy, ACOG Committee Opinion No. 548, 2013
Weight Gain During Pregnancy: Reexamining the Guidelines, Institute of Medicine & National Research Council, 2009
Pregnancy Weight Gain Calculator
Use this pregnancy weight gain calculator to estimate recommended weight gain from your pre-pregnancy BMI and current week.
Kimberly Langdon, MD
Kimberly Langdon, MD, is a retired, board-certified obstetrician/gynecologist with 19 years of clinical practice, trained at The Ohio State University.
Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How Pregnancy Weight Gain Targets Are Calculated
There’s no single healthy weight gain number for pregnancy, it depends entirely on where you started. This calculator uses your pre-pregnancy BMI to place you in one of four categories, each with its own recommended total gain and expected pace through the second and third trimesters.
What This Calculator Measures
This gives you a recommended total gain range and an estimate of where you should be by your current week, not a verdict on whether your actual gain so far is right or wrong. Individual pregnancies vary.
Step 1: Determine Your Pre-Pregnancy BMI Category
We calculate your BMI from your pre-pregnancy height and weight, then place it into one of four categories¹.
Pre-Pregnancy BMI | Category |
Below 18.5 | Underweight |
18.5 to 24.9 | Normal Weight |
25.0 to 29.9 | Overweight |
30.0 and above | Obesity |
Step 2: Apply the Recommended Gain Range for Your Category
Each category carries its own total gain range for a singleton pregnancy, endorsed by ACOG¹ based on Institute of Medicine guidelines².
Category | Recommended Total Gain |
Underweight (BMI below 18.5) | 28 to 40 lb (12.5 to 18 kg) |
Normal weight (BMI 18.5 to 24.9) | 25 to 35 lb (11.5 to 16 kg) |
Overweight (BMI 25 to 29.9) | 15 to 25 lb (7 to 11.5 kg) |
Obesity (BMI 30 and above) | 11 to 20 lb (5 to 9 kg) |
Step 3: Track Weekly Gain in the Second and Third Trimester
Most weight gain happens after the first trimester, which typically accounts for only 1 to 4.5 lb of the total². We apply a steady weekly gain rate for your BMI category to estimate your expected progress at your current week, assuming a singleton pregnancy.
How This Calculator Computes Your Result
Enter your pre-pregnancy height, weight, and current week of pregnancy above. We calculate your pre-pregnancy BMI, match it to a category, and estimate both your total recommended range and your expected progress at your current week.
A Note on Accuracy
These ranges are general guidance for a singleton pregnancy. Your OB-GYN or midwife may recommend a different target based on your health history, multiples, or pre-existing conditions.
Frequently Asked Questions
How much weight should I gain during pregnancy?
It depends on your pre-pregnancy BMI. Most guidelines recommend 25 to 35 lb for a normal BMI, with higher ranges for underweight and lower ranges for overweight or obese pre-pregnancy BMI¹.
Is this calculator accurate for twin pregnancies?
No. This calculator is designed for singleton pregnancies. Twin and multiple pregnancies have separate, higher recommended weight gain ranges.
What if I'm gaining weight faster or slower than recommended?
Some variation week to week is normal. If your gain is consistently far outside the recommended range, talk to your OB-GYN or midwife about your individual plan.
Does this calculator account for the first trimester?
Yes. First trimester gain is typically small, about 1 to 4.5 lb total², with most of the recommended gain occurring during the second and third trimesters.
Sources
Weight Gain During Pregnancy, ACOG Committee Opinion No. 548, 2013
Weight Gain During Pregnancy: Reexamining the Guidelines, Institute of Medicine & National Research Council, 2009