How much weight gain is normal in pregnancy
The recommended range for weight gain in pregnancy does not depend on what you weigh now, but on your body mass index before pregnancy. That is why two women can gain different amounts and both be completely fine. This calculator gives you an approximate range and pace. It is a guide for a conversation with your doctor or midwife, not a grade.
What the recommended range is
The most widely used guidelines tie the range to your pre-pregnancy body mass index. Women who were underweight are advised to gain the most, roughly 12.5 to 18 kilograms. For a normal index the range is roughly 11.5 to 16 kilograms. For overweight it is roughly 7 to 11.5, and for obesity roughly 5 to 9 kilograms. With twins the ranges are higher and are set by your doctor.
Where the weight actually goes
Very little of it is body fat. At the end of pregnancy the baby weighs about 3.5 kilograms, the placenta about half a kilo to one, amniotic fluid about one, the uterus about one, increased blood volume about 1.5, retained fluid about 1.5, and the breasts about one kilogram. The remainder is the reserve your body builds for late pregnancy and breastfeeding. Broken down like that, the number on the scale stops looking like something you did wrong.
How it is distributed through pregnancy
In the first trimester the gain is usually very small, often between half a kilo and two, and some women lose a little because of nausea. That alone is not a cause for concern. From the second trimester the pace settles at roughly a third to half a kilogram per week for a woman with a normal pre-pregnancy index. The overall range matters more than any single week, because weight fluctuates naturally with fluid.
What if you are outside the range
The range is a guide, not a line you either crossed or did not. Gaining too little is associated with lower birth weight, and gaining too much with a higher risk of gestational diabetes, high blood pressure and a more difficult birth. If you are outside the range it is worth discussing with your doctor, but the answer is almost never a diet. It is usually food quality and regular moderate activity.
Why you do not diet during pregnancy
Deliberately restricting intake to lose weight is not recommended during pregnancy, because the baby needs nutrients precisely during the period of fastest growth. The goal is not to stop the gain but to direct it: enough protein, enough iron and folate, and regular activity that maintains strength. For women with obesity a doctor sometimes sets a lower target range, but that is a decision for a doctor, not a calculator.
What happens after birth
Roughly five to six kilograms go immediately, between the baby, the placenta and the amniotic fluid. Much of the retained fluid follows over the next few weeks. The rest comes off gradually, at a pace that depends on breastfeeding, sleep, food and activity. Months is the realistic timeframe rather than weeks, and that is the normal course rather than falling behind.
How a kinesiologist helps
A kinesiologist looks past the number on the scale at what is actually happening: how much strength you have, how you sleep, whether anything hurts and how you move. The programme is matched to your trimester and your energy, and after birth it builds a return that starts from the pelvic floor and abdominal wall rather than from calorie burn. The goal is a body that works well, and weight settles as a consequence.
Written by Ozana Brkić, MSc in Kinesiology, a certified kinesiologist specialising in prenatal and postnatal training. Content last reviewed: August 2026.