Pregnancy Weight Gain Calculator
Compare your weight change with broad pregnancy weight-gain guidance based on pre-pregnancy BMI, gestational week, and whether you are carrying one baby or twins.
Your details
Enter 0–42 weeks.
Your estimate
Recommended total gain
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Enter your details, then select Calculate.
How to use this pregnancy weight gain calculator
- Select metric or US units and whether you are carrying one baby or twins.
- Enter your height, pre-pregnancy weight, current weight, and gestational week.
- Review your pre-pregnancy BMI category, total recommended range, current change, and broad pacing guidance.
Understanding the estimate
Recommendations begin with pre-pregnancy body mass index (BMI). For a singleton pregnancy, commonly used total-gain ranges are 28–40 lb for an underweight BMI, 25–35 lb for a normal BMI, 15–25 lb for an overweight BMI, and 11–20 lb for an obese BMI.
Weight gain is rarely perfectly linear. The current-week range shown here is only a broad planning guide: it allows about 1.1–4.4 lb (0.5–2 kg) in the first trimester, followed by a BMI-based weekly range. Twin pregnancies need more individualized monitoring, so this tool shows the recognized total range without inventing a week-by-week target.
Frequently asked questions
Does this diagnose healthy or unhealthy weight gain?
No. Weight changes can reflect fetal growth, fluid, placenta, blood volume, nutrition, illness, or other factors. Only a qualified clinician who knows your pregnancy can interpret your trend.
Why use pre-pregnancy BMI?
Major clinical guidance uses BMI before pregnancy to group recommended total weight-gain ranges. BMI is a screening measure, not a complete health assessment.
What if I am carrying triplets or more?
This calculator is not designed for higher-order multiple pregnancies. Ask your obstetric professional for individualized targets and monitoring.
Should I diet during pregnancy if the result says above the guide?
Do not begin a restrictive diet based on this estimate. Discuss nutrition, activity, symptoms, and weight changes with your prenatal care professional.
Important medical notice
This educational calculator is not medical advice, a diagnosis, or a substitute for prenatal care. Contact your healthcare professional about rapid gain or loss, severe swelling, persistent vomiting, headache, vision changes, breathing difficulty, or any concern. Recommendations can differ for adolescents, people with certain health conditions, and multiple pregnancies.
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