Pregnancy Weight Gain Calculator

Offers guidance on how much weight should be gained safely during pregnancy (be it singular or multiple).

Weight before pregnancy:
Is it a multiple pregnancy?
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Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.

Pregnancy weight gain guidelines

Health regulations on pregnancy weight depend on the weight category of the expectant mother at the start of the pregnancy and of how many babies are carried. This calculator uses such guidance to recommend the total weight gain as well as breaks it down for each of the three trimesters.

Below are two charts that summarize the total weight gain in lbs and kgs, depending on the mother’s body mass index and whether the pregnancy is multiple.

Pregnancy with one baby

Weight situation BMI Lbs to put on Kg to put on
Underweight 28 – 40 13 – 18
Normal weight 25 – 35 11 – 16
Overweight 15 – 25 7 – 11
Obese 11 – 20 5 – 9

Pregnancy with twins

Weight situation BMI Lbs to put on Kg to put on
Underweight 28 – 40 13 – 18
Normal weight 37 – 54 17 – 25
Overweight 31 – 50 14 – 23
Obese 25 – 42 11 – 19

The impact of weight at the start of pregnancy

The weight category of the expectant mother, one of the starting points of weight recommendations, is expressed based on body mass index (BMI) values. BMI is an indicator of weight in relation to height and reflects whether a person is underweight, of normal weight, overweight or obese:

BMI range Category of weight
< 18.5 Underweight
18.5 and 25 Normal weight
25 and 29 Overweight
> 30 Obese

If the expectant mother is classed as underweight, there are higher risks associated with the pregnancy (i.e. risk of miscarriage or fetal complications) than in the case of a normal weight mother.

If the expectant mother is overweight or obese, weight during pregnancy must be monitored as to not exceed guidelines, because there is an increased risk of early labour and premature birth.


Wylie L. (2005) Essential anatomy and physiology in maternity care (2nd ed.) Edinburgh: Churchill Livingstone.

Bateson P. (2001) Fetal experience and good adult design. International Journal of Epidemiology 30 (5): 928–934

Institute of Medicine. (2009) Weight Gain During Pregnancy: Reexamining the Guidelines.

Specialty: Obstetrics Gynecology

System: Reproductive

Article By: Denise Nedea

Published On: April 14, 2020

Last Checked: April 14, 2020

Next Review: April 14, 2025