How much weight gain is normal during pregnancy? The answer depends mainly on your starting weight. Based on your initial BMI, our calculator shows you how much weight gain is considered normal up to your current week of pregnancy—including a weekly plan leading up to delivery.
Why There Isn’t Just One Number
The common rule of thumb of 12 kilograms applies only to women who are of normal weight at the start of pregnancy. Those who were underweight or overweight beforehand have different guidelines.
The recommendations of the Institute of Medicine, which also serve as a guide in Germany, are the standard. They classify the range based on your pre-pregnancy BMI—that is, the weight you had before conception.
An Overview of the Guidelines
| Pre-pregnancy BMI | Category | Total weight gain | Per week starting at gestational week 14 |
| Below 18.5 | Underweight | 12.5–18 kg | 0.44–0.58 kg |
| 18.5 – 24.9 | Normal weight | 11.5 – 16 kg | 0.35–0.50 kg |
| 25–29.9 | Overweight | 7 – 11.5 kg | 0.23–0.33 kg |
| 30 or more | Obesity | 5–9 kg | 0.17–0.27 kg |
For twins, the values are significantly higher: 16.8 to 24.5 kilograms for normal weight, 14.1 to 22.7 for overweight, and 11.3 to 19.1 for obesity. To date, there are no reliable recommendations for underweight women carrying twins.
How weight gain is distributed over the weeks
Not much happens in the first trimester: A total weight gain of 0.5 to 2 kilograms is typical. Some women even lose weight temporarily due to nausea—but this, too, is no cause for concern at first.
Starting in the 14th week, the weight gain becomes more consistent. From then on, the amount listed in the table is added week by week. This is exactly how our weekly plan works: It spreads the weight gain across the weeks of pregnancy and shows you a range for each stage instead of a single number.
Here’s an example: If you’re 168 centimeters tall and weigh 65 kilograms to start, your BMI is 23.0, which is within the normal range. By the 24th week, you can therefore expect to gain about 4.3 to 7.5 kilograms—bringing your weight to approximately 69 to 73 kilograms.
What the weight gain consists of
Only part of the weight gain is due to the baby. At term, the baby weighs an average of 3.3 to 3.5 kilograms. Added to this are amniotic fluid and the placenta, each weighing about half a kilogram to one kilogram, as well as the enlarged uterus, increased blood volume, retained water, and the breasts.
The rest consists of energy reserves for childbirth and breastfeeding. These reserves are not a flaw but are intended—the body builds them up specifically for this purpose.
When the trend deviates
Individual weeks with more or less weight gain are normal. Fluid balance, digestion, and daily energy levels fluctuate even more during pregnancy than usual. What matters is the trend over several weeks.
It becomes a cause for concern if weight stagnates for an extended period, rises sharply all at once, or is accompanied by significant water retention. This should be addressed during prenatal care, not through a calculator. Weight-loss diets are generally not recommended during pregnancy.
Exercise and Physical Activity During Pregnancy
For healthy pregnant women without complications, professional organizations recommend about 150 minutes of moderate exercise per week. Good options include walking, swimming, cycling on a stationary bike, moderate strength training, and specialized classes. The intensity should be such that you can still carry on a conversation—the training heart rate calculator will help you gauge your intensity.
This is a growing trend for gyms: prenatal and postnatal classes, equipment with easy access, and trained staff are key factors for many expectant mothers. The calorie burn calculator tells you exactly how many calories a workout session burns.
What the calculator can’t do
It uses average values based on guidelines. It doesn’t take into account your medical history or conditions such as gestational diabetes, high blood pressure, or a multiple pregnancy with complications.
Your prenatal care with your doctor or midwife therefore remains the most important factor. Use these values as a guide between appointments, not as a definitive assessment. By the way, you can also determine your baseline BMI using our BMI calculator.
Frequently Asked Questions / FAQ
When does weight gain start during pregnancy?
You’ll usually start to notice it in the second trimester. In the first trimester, a weight gain of 0.5 to 2 kilograms is typical; if you’re experiencing severe nausea, you may gain even less or nothing at all.
Is gaining too little weight a problem?
Consistently low weight gain can be associated with a lower birth weight and preterm birth. If your weight remains stagnant for several weeks, bring this up at your next prenatal appointment.
Can I lose weight during pregnancy?
Intentional weight loss is not recommended, even if you start out at a high weight. However, if you’re obese, the recommended weight gain is significantly lower—this will be monitored individually during your prenatal care.
Do these guidelines also apply to twins?
No, there are separate ranges for that. The calculator takes them into account if you select “twins” as the type of pregnancy.
How often should I weigh myself?
Once a week is perfectly sufficient, preferably in the morning and always under the same conditions. Weighing yourself daily mainly reflects fluctuations in water weight.
Editorial team at fitnessmarkt.de
Image source: #24440856 prostooleh / freepik.com
Published on: 2 October 2026