Pregnancy Weight Gain Calculator
Estimate guideline-based pregnancy weight gain ranges from pre-pregnancy BMI, gestational week, and current weight for singleton pregnancies.
Last updated: 2026-03-27
Pregnancy weight gain calculator
Enter your values
Compare current gain with the guideline band for your gestational week and pre-pregnancy BMI.
Recommended Gain by This Week
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Enter pre-pregnancy weight, current weight, height, units, and gestational week to estimate the guideline range.
Calculation History(0)
Example calculations
Tap an example to prefill the calculator with sample values.
Normal-weight second trimester
145 lb pre-pregnancy, 64 in tall, currently 160 lb at week 28
A common singleton-pregnancy check where the goal is to compare current gain against the guideline band by week.
Result: The calculator compares actual gain with the week-specific guideline range instead of only the final delivery target.
Metric entry in early third trimester
68 kg pre-pregnancy, 170 cm, now 76 kg at week 30
Useful when entering clinician-facing measurements in metric rather than converting first.
Result: The recommended range is shown in the selected unit while the BMI category still follows the same guideline cutoffs.
Higher-BMI first trimester
190 lb pre-pregnancy, 64 in, now 193 lb at week 12
Early-pregnancy checks are usually more about broad range placement than a narrow week-by-week target.
Result: First-trimester guidance is much wider and less linear than later weekly pacing.
How the pregnancy weight-gain range is estimated
The calculator computes pre-pregnancy BMI from your starting weight and height, then maps that BMI to the singleton-pregnancy gain ranges used in the IOM 2009 guideline and summarized by ACOG. Total recommended gain and the later-pregnancy weekly pace both come from that BMI band.
To estimate where the guideline range sits at your current week, the tool uses a small first-trimester gain range and then adds the BMI-specific weekly pace after week 13. That produces a practical by-this-week comparison point rather than only a delivery-day target.
Pregnancy weight-gain FAQs
Use the range as a screening guide for singleton pregnancies, not as individualized medical advice.
Why does the recommended range depend on pre-pregnancy BMI?
Because the guideline bands are set by pre-pregnancy BMI category, not by current weight alone. The target total gain and the recommended weekly pace in later pregnancy differ for underweight, normal-weight, overweight, and obesity categories.
Does this work for twins or higher-order pregnancies?
No. This calculator is for singleton pregnancies only. Multiple gestations use different weight-gain guidance and should be reviewed directly with a prenatal clinician.
What if my actual gain is outside the band?
Use that as a check-in prompt, not a diagnosis. Many factors can affect short-term gain, and your own clinician may have reasons to individualize guidance. Persistent or large deviations deserve a conversation at prenatal visits.
Embed this calculator
Copy the code below to embed this calculator on your website or blog. It's free — no API key needed.
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Optional: auto-resize script
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</script> Related tools
Pair pregnancy-weight tracking with timeline and BMI context calculators.
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BMI Calculator
Check the BMI framing used before pregnancy-weight-gain targets are assigned.
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Use adjacent reproductive-health planning tools for earlier-cycle timing questions.
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Medical disclaimer
This calculator is for educational use and follows general singleton-pregnancy guideline bands. It does not replace prenatal care or individualized advice from your obstetric clinician or midwife.
Talk to your healthcare team if you are carrying multiples, have hyperemesis, gestational diabetes, hypertension, eating-disorder history, or any clinician-directed weight target that differs from standard guidance.