Pregnancy Weight Gain by Trimester Calculator
See recommended pregnancy weight gain broken down by trimester.
Assumptions used in this calculation
- Simplified distribution: First-trimester gain is treated as a fixed 0.5–2 kg range per ACOG guidance regardless of BMI category; consult your doctor for personalized guidance.
About this calculator
Knowing your total recommended pregnancy weight gain doesn't tell you how to pace it across nine months, and weight gain isn't spread evenly, most of it happens in the second and third trimesters rather than the first. This calculator breaks the IOM's total-gain guideline into per-trimester targets: enter your pre-pregnancy height and weight to establish your BMI category and total recommended range, and it applies a fixed first-trimester allowance (0.5-2 kg per ACOG guidance, since fetal growth is minimal early on) with the remainder of the total range split evenly across the second and third trimesters. That breakdown is more useful for pacing than a single total number, since it lets you check whether your gain at, say, the end of trimester two looks on track rather than only being able to assess progress at the very end of pregnancy. As with the overall guideline, this is based on singleton pregnancies and general IOM categories, not a personalized medical recommendation.
Worked example
165cm, 60kg pre-pregnancy
Result: 11.5–16 kg total, split by trimester
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