Pregnancy Weight Gain Calculator
Find your recommended total pregnancy weight gain based on your pre-pregnancy BMI, using Institute of Medicine guidelines for a healthy pregnancy.
Why pregnancy weight gain matters
Gaining a healthy amount of weight during pregnancy supports your baby's growth and development and helps protect your own health. Gaining too little can increase the risk of a low-birth-weight baby, while gaining too much can raise the risk of complications such as gestational diabetes, high blood pressure and a more difficult delivery, and can make it harder to return to a healthy weight afterward. The right amount depends largely on your weight before pregnancy.
How the recommendation is calculated
This calculator uses the widely adopted Institute of Medicine (IOM) guidelines, which base recommended total weight gain on your pre-pregnancy body mass index (BMI). Women who started at a lower BMI are advised to gain more, and those who started at a higher BMI to gain less. The ranges shown are for a single baby (singleton pregnancy). For twins or other multiples, recommended weight gain is higher, and your provider will advise specifically.
How gain is distributed
Weight gain is not evenly spread across pregnancy. In the first trimester, gain is usually small — often just one to two kilograms — as the baby is still tiny. Most weight is gained steadily through the second and third trimesters as your baby grows and your body changes to support the pregnancy. The weight comes from many sources: the baby, placenta, amniotic fluid, increased blood volume, breast tissue and fat stores for breastfeeding.
A guide, not a strict target
These ranges are population guidelines, not rigid rules for every individual. Your own healthy target should be set with your midwife or doctor, who will consider your complete health picture, any pregnancy complications and how your pregnancy progresses. Focus on nourishing food and gentle activity rather than the scale alone. If you have concerns about gaining too much or too little, your healthcare provider is the best source of personalised guidance.
Frequently Asked Questions
It depends on your pre-pregnancy BMI. IOM guidelines for a single baby recommend about 12.5–18 kg if you were underweight, 11.5–16 kg if normal weight, 7–11.5 kg if overweight, and 5–9 kg if obese. This calculator gives your specific range.
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Sources & References
- 1.Institute of Medicine (IOM). Weight Gain During Pregnancy: Reexamining the Guidelines.
- 2.American College of Obstetricians and Gynecologists (ACOG). Weight Gain During Pregnancy.
- 3.Centers for Disease Control and Prevention (CDC). Weight Gain During Pregnancy.
LifeCheckIQ content is based on peer-reviewed research, recognised clinical guidelines, and authoritative medical sources, and is reviewed by Deborah Adotso, General Nurse, for clinical accuracy.
Medical Disclaimer: This tool is for informational and educational purposes only. Results are not a medical diagnosis. Always consult a qualified healthcare professional for medical advice, diagnosis, or treatment. In an emergency, call your local emergency number or visit the nearest hospital immediately.