Pregnancy Weight Gain Calculator
Track recommended weight gain during pregnancy based on your pre-pregnancy BMI and current week.
Enter Your Values
Enter your values and press Calculate — you will get the result, its method, the inputs used and confidence, plus copy, print and share options.
How this calculator works
IOM/NAM pregnancy weight gain v1.0.0
Total and weekly gestational weight-gain ranges by pre-pregnancy BMI (singletons and twins).
- Applies to
- Pregnant adults (US population reference)
- Assumptions
- Pre-pregnancy BMI category
- Limitations
- Ranges, not targets; individualized by prenatal care team
- Output
- kg
- Last reviewed
- 2026-06-01
Sources
- Institute of Medicine / National Academies. Weight Gain During Pregnancy: Reexamining the Guidelines. National Academies Press, 2009. doi:10.17226/12584.
About the Pregnancy Weight Gain Calculator
Gaining weight during pregnancy is healthy and necessary, it supports your baby's growth and your own changing body, and this calculator estimates a recommended weight-gain range based on your pre-pregnancy BMI and how far along you are. The guidance it reflects comes from established recommendations (such as those from the Institute of Medicine), giving you a sensible range to discuss with your provider.
I want to lead with reassurance: pregnancy is absolutely not the time for dieting or weight worry. The goal is healthy, gradual gain that nourishes you and your baby. This tool offers a helpful range, and your prenatal care team tailors it to you, because every pregnancy is individual.
Why weight gain matters in pregnancy
The weight you gain supports many things at once: your growing baby, the placenta, amniotic fluid, increased blood volume, and energy stores for breastfeeding. Gaining within a healthy range is associated with better outcomes for both you and your baby, while gaining far too little or too much can carry risks. That is why providers keep a gentle eye on the trend, not to judge, but to support a healthy pregnancy.
How the recommended range is set
The recommended total gain depends largely on your pre-pregnancy BMI. As a general guide, someone who started at a normal BMI is often advised to gain around 25 to 35 pounds total, with a higher range for those who began underweight and lower ranges for those who began overweight or with obesity. The calculator uses your starting BMI and current week to estimate where your gain might sensibly fall.
Gaining gradually
Healthy gain is not evenly spread; most of it happens in the second and third trimesters. The first trimester often brings little gain (and nausea can even cause a small loss, which is usually fine), while a steadier, gradual increase follows as the baby grows. The calculator reflects this pattern, so do not be alarmed if early gain is minimal. Slow and steady, guided by your provider, is exactly right.
Nourishment over numbers
Rather than fixating on the scale, focus on nourishing food and gentle, approved activity. You do not need to eat for two in terms of calories, the extra energy needed is more modest than people think, and quality matters: protein, fruit and vegetables, whole grains, dairy or alternatives, and key nutrients like folate, iron and calcium. Any concern about gaining too much or too little belongs in a kind conversation with your provider, never in self-imposed dieting.
Sources & method
This calculator uses established, peer-reviewed formulas and reference ranges from recognized health and nutrition authorities. Results are estimates for general education, not a medical diagnosis. For decisions about your health, consult a qualified clinician. Reviewed by Macro & Meals Editorial Team, Content editor.
Frequently Asked Questions
It depends largely on your pre-pregnancy BMI. As a general guide, someone starting at a normal BMI is often advised to gain around 25 to 35 pounds total, with more for those who began underweight and less for those who began with overweight or obesity. The calculator estimates a range from your starting BMI and current week.
Yes. Most healthy weight gain happens in the second and third trimesters, while the first trimester often brings little gain, and nausea can even cause a small loss, which is usually fine. A steadier, gradual increase follows as the baby grows.
Pregnancy is not the time for dieting or weight restriction. If you are concerned about gaining too much or too little, raise it kindly with your prenatal provider, who can guide healthy eating and activity. The goal is nourishment for you and your baby, not weight loss.
Not in terms of calories. The extra energy needed in pregnancy is more modest than the phrase suggests. What matters most is quality: protein, fruit and vegetables, whole grains, dairy or alternatives, and key nutrients like folate, iron and calcium, alongside healthy gradual weight gain.
