Free · IOM-based
Pregnancy Weight Gain Calculator
Find out how much weight you should gain during pregnancy based on the Institute of Medicine (IOM) guidelines. Enter your pre-pregnancy weight and height, select your current week, and see your healthy range — adjusted for twin pregnancy if applicable.
Your data stays in your browser. Sakina does not store any inputs.
Why pregnancy weight gain matters
Gaining within the recommended range reduces the risk of preterm birth, gestational diabetes, hypertension, large-for-gestational-age babies and postpartum weight retention. Too little gain is linked to low birth weight and developmental issues; too much increases complications for both mother and baby.
IOM 2009 guidelines (singleton)
- Underweight (BMI below 18.5): 12.7–18.1 kg (28–40 lb).
- Normal weight (BMI 18.5–24.9): 11.3–15.9 kg (25–35 lb).
- Overweight (BMI 25–29.9): 6.8–11.3 kg (15–25 lb).
- Obese (BMI 30+): 5–9.1 kg (11–20 lb).
Twins
For twin pregnancies, increase each range by roughly 50%. A normal-BMI mother carrying twins is advised to gain about 17–25 kg total.
Typical trajectory
Gain in the first trimester is minimal (0.5–2 kg). From weeks 13 onwards, normal-BMI mothers typically gain around 0.4–0.5 kg per week — slightly less if overweight, slightly more if underweight.
Frequently asked questions
What if I gained too much in one week?
A single spike is usually fluid, not fat. Monitor trend over 2–3 weeks; consistently high gains should be discussed with your midwife.
Can I diet to lose weight during pregnancy?
No. Pregnancy is not the time for calorie restriction even if you are overweight. The focus is on nutrient density and avoiding excess gain, not loss.
Is weight gain different by trimester?
Yes. Most gain happens in trimester 2 and 3. First trimester adds around 0.5–2 kg total; the rest is steady weekly gain.
Does breastfeeding help me lose pregnancy weight?
Yes, moderately. Exclusively breastfeeding burns roughly 400–500 extra calories per day and supports natural return to pre-pregnancy weight over 6–12 months.
Does this calculator save my data?
No. Calculations run in your browser only.
Related tools
Calculations based on standard obstetric formulas and WHO guidance. For medical decisions, always consult your doctor or midwife.