See the recommended weight gain for your stage of pregnancy.
Updated Sep 2026Fill in the fields and press Calculate. Every range comes from the sources listed under the tool.
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Sources
- Weight Gain During Pregnancy: Reexamining the Guidelines National Academies Press (Institute of Medicine, 2009)
- Weight Gain During Pregnancy (Committee Opinion No. 548) American College of Obstetricians and Gynecologists (ACOG)
- Managing your weight gain during pregnancy: MedlinePlus Medical Encyclopedia MedlinePlus (NIH)
- Weight Gain During Pregnancy - NCBI Bookshelf NCBI Bookshelf (National Academies / NIH)
How Much Weight Should You Gain During Pregnancy?
The answer depends on where you started. The Institute of Medicine guidelines, used by doctors worldwide, set gain targets based on your pre-pregnancy BMI. This pregnancy weight gain calculator works out that BMI from your height and pre-pregnancy weight, then shows the total range the Institute of Medicine gives for it and roughly where that range runs at your current week.
- One baby
- Twins
Recommended Total Gain (One Baby)
| Pre-pregnancy BMI | Recommended gain |
|---|---|
| Under 18.5 | 12.7 to 18.1 kg (28 to 40 lb) |
| 18.5 to 24.9 | 11.3 to 15.9 kg (25 to 35 lb) |
| 25 to 29.9 | 6.8 to 11.3 kg (15 to 25 lb) |
| 30 and above | 5.0 to 9.1 kg (11 to 20 lb) |
Twin pregnancies run higher: roughly 16.8 to 24.5 kg (37 to 54 lb) for a healthy starting BMI. Most gain happens in the second and third trimesters; the first trimester typically adds only 0.5 to 2 kg in total.
Where the Weight Actually Goes
At full term, the baby accounts for only about 3.5 kg of the total. The rest is the placenta, amniotic fluid, a larger uterus and breasts, extra blood volume, retained fluid, and fat stores that fuel breastfeeding. Gaining within your range is not about appearance; it is linked to lower rates of gestational diabetes, delivery complications, and postpartum weight retention.
Expecting and still early? Get your timeline first with the due date calculator, and for the cycle before it, the menstrual cycle phases.
Frequently Asked Questions
What if I am gaining too fast?
A single fast week is normal noise; a fast month is worth a conversation with your provider. Do not diet or restrict on your own while pregnant. Usually small changes to snacks, drinks, and daily walking bring the curve back in line.
What if I am not gaining enough?
Mention it at your next appointment, especially in the second and third trimesters. Nausea, food aversions, or a fast metabolism can all play a role, and your provider can rule out anything that needs attention.
Do I really need extra calories while pregnant?
Barely any in the first trimester. Guidelines add roughly 340 extra calories a day in the second trimester and 450 in the third. That is a sandwich, not a second dinner.
How fast should the weight come off after birth?
Slowly. Around half the gain typically goes within six weeks, and the rest over several months. Breastfeeding, sleep, and gentle activity matter more than any deadline.
Sources
- Weight Gain During Pregnancy: Reexamining the Guidelines · National Academies Press (Institute of Medicine, 2009)
- Weight Gain During Pregnancy (Committee Opinion No. 548) · American College of Obstetricians and Gynecologists (ACOG)
- Managing your weight gain during pregnancy: MedlinePlus Medical Encyclopedia · MedlinePlus (NIH)
- Weight Gain During Pregnancy – NCBI Bookshelf · NCBI Bookshelf (National Academies / NIH)
This calculator is for general information only. Your provider may set different targets for your situation, and their advice comes first.