Pregnancy Weight Gain Tracker
Check your weight gain against medical guidelines based on your pre‑pregnancy BMI and current week.
Fill in the fields above to see your results.
How much weight should you gain in pregnancy?
Quick answer: Recommended pregnancy weight gain depends on your pre‑pregnancy BMI. As a general guide: underweight 12.5–18 kg (28–40 lb), normal weight 11.5–16 kg (25–35 lb), overweight 7–11.5 kg (15–25 lb), and obese 5–9 kg (11–20 lb). These are totals for a single baby by the end of pregnancy.
These ranges come from Institute of Medicine (IOM) guidelines, the most widely used reference for prenatal weight gain. Gain is usually slow in the first trimester, roughly 0.5 to 2 kg total, then follows a fairly steady weekly pace through the second and third trimesters. That pace is faster for people who start pregnancy underweight and slower for those who start overweight or obese.
Weight gain during pregnancy isn’t just body fat — it includes the baby, placenta, amniotic fluid, extra blood volume, and increased breast and uterine tissue. Gaining within your recommended range supports healthy fetal growth, while gaining well above or below it is linked to a higher chance of complications, which is why providers track it at each visit.
Recommended gain by pre‑pregnancy BMI
| Pre‑pregnancy BMI | Category | Total gain | 2nd–3rd trimester pace |
|---|---|---|---|
| Below 18.5 | Underweight | 12.5–18 kg (28–40 lb) | ~0.51 kg/week |
| 18.5–24.9 | Normal weight | 11.5–16 kg (25–35 lb) | ~0.42 kg/week |
| 25–29.9 | Overweight | 7–11.5 kg (15–25 lb) | ~0.28 kg/week |
| 30 and above | Obese | 5–9 kg (11–20 lb) | ~0.22 kg/week |
Figures above are for a single baby. Twin and multiple pregnancies have separate, higher targets — ask your provider for guidance specific to your pregnancy.
Frequently asked questions
How much weight should I gain during pregnancy?
It depends on your pre‑pregnancy BMI. General ranges are 12.5–18 kg if underweight, 11.5–16 kg at a normal weight, 7–11.5 kg if overweight, and 5–9 kg if obese, for a single baby.
What if I’m gaining faster or slower than recommended?
Some variation week to week is normal. If your pace is consistently well above or below your recommended range, mention it at your next prenatal visit so your provider can check on you and the baby.
Does pre‑pregnancy BMI really affect how much I should gain?
Yes. Guidelines recommend more total gain for people who start pregnancy underweight and less for those who start overweight or obese, since starting body reserves differ.
Is weight gain different for twins?
Yes, twin and multiple pregnancies have higher recommended ranges than a single baby. This tool is built for singleton pregnancies — ask your provider for numbers specific to multiples.
When should I be concerned about my weight gain?
Sudden, rapid gain (especially with swelling or headaches) or very little gain over several weeks are both worth mentioning to your provider promptly rather than waiting for your next scheduled visit.
Where does the extra weight actually go?
It’s spread across the baby, placenta, amniotic fluid, extra blood and fluid volume, a larger uterus, and breast tissue — not solely body fat.
Does this tracker replace advice from my doctor?
No. It’s a general guide based on published guidelines. Your provider tracks your specific health history and should always be your main source for advice on weight during pregnancy.