Gain Weight During Pregnancy Calculator
Pregnancy Weight Gain Calculator works out Pre-pregnancy BMI and BMI category from Units, Pre-pregnancy weight and Height. The default figures on this page give recommended total gain, low of 11.5 kg; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
4 steps
- Pre-pregnancy BMI = 60 kg / (1.65 m)^2 = 22.039 kg/m2.
- IOM 2009 category: Normal weight (BMI 18.5 to 24.9).
- Recommended total gain (singleton): 11.5 to 16 kg.
- Recommended by week 20 = first-trimester allowance + rate x (20 - 13): 0.5 + 0.35 x 7 = 2.95 kg to 2 + 0.5 x 7 = 5.5 kg.
Recommended gain week by weektable
| week | lowKg | highKg | lowLb | highLb |
|---|---|---|---|---|
| 4 | 0.5 | 2 | 1.1 | 4.4 |
| 6 | 0.5 | 2 | 1.1 | 4.4 |
| 8 | 0.5 | 2 | 1.1 | 4.4 |
| 10 | 0.5 | 2 | 1.1 | 4.4 |
| 12 | 0.5 | 2 | 1.1 | 4.4 |
| 14 | 0.85 | 2.5 | 1.9 | 5.5 |
| 16 | 1.55 | 3.5 | 3.4 | 7.7 |
| 18 | 2.25 | 4.5 | 5 | 9.9 |
| 20 | 2.95 | 5.5 | 6.5 | 12.1 |
| 22 | 3.65 | 6.5 | 8 | 14.3 |
| 24 | 4.35 | 7.5 | 9.6 | 16.5 |
| 26 | 5.05 | 8.5 | 11.1 | 18.7 |
| 28 | 5.75 | 9.5 | 12.7 | 20.9 |
| 30 | 6.45 | 10.5 | 14.2 | 23.1 |
| 32 | 7.15 | 11.5 | 15.8 | 25.4 |
| 34 | 7.85 | 12.5 | 17.3 | 27.6 |
| 36 | 8.55 | 13.5 | 18.8 | 29.8 |
| 38 | 9.25 | 14.5 | 20.4 | 32 |
| 40 | 9.95 | 15.5 | 21.9 | 34.2 |
Its 4 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
3 sources
What the Pregnancy Weight Gain Calculator calculates
Works out the recommended total and week-by-week gestational weight gain from pre-pregnancy BMI using the 2009 IOM/NRC guidelines, and compares it with the weight gained so far.
How to use this Pregnancy Weight Gain Calculator
Enter Units, Pre-pregnancy weight, Height and Pre-pregnancy BMI (optional). Pre-pregnancy BMI updates as you type, and “Use a worked example” loads checked figures you can adjust. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Pre-pregnancy BMI, BMI category and Recommended total gain, low.
The method follows Institute of Medicine and National Research Council. Weight Gain During Pregnancy: Reexamining the Guidelines. Washington DC: The National Academies Press, 2009, CDC, Weight Gain During Pregnancy and WHO adult BMI categories, adopted by the IOM for the pre-pregnancy classification.
Normal pre-pregnancy BMI at 25 weeks example
With Units: metric, Pre-pregnancy weight: 60, Height: 165, Weeks pregnant: 25, the calculator returns Pre-pregnancy BMI: 22.0385675, Recommended total gain, low: 11.5, Recommended total gain, high: 16. This example is checked against an independent source in the test suite.
What you can compare
Change one input at a time to see how it affects Pre-pregnancy BMI, BMI category and Recommended total gain, low. The inputs you can vary are Units, Pre-pregnancy weight, Height, Pre-pregnancy BMI (optional), Weeks pregnant and Current weight.
Understanding Pre-pregnancy BMI, BMI category and Recommended total gain, low
These are population guidelines for healthy pregnancies, not a personal target. Gaining outside the range is common and is not by itself a problem. Weight during pregnancy should be discussed with the midwife or obstetrician managing your care, who will account for your history, plurality and any complications.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
How much weight do you gain during pregnancy?
On the figures this page opens with — pre-pregnancy weight 60, height 165 and weeks pregnant 25 — the recommended total gain, low is 11.5 kg. No single number fits everyone: change any figure above and the answer updates as you type, with each step of the arithmetic beside it.
Is it normal to gain 60 pounds during pregnancy?
Works out the recommended total and week-by-week gestational weight gain from pre-pregnancy BMI using the 2009 IOM/NRC guidelines, and compares it with the weight gained so far. On the figures this page opens with — pre-pregnancy weight 60, height 165 and weeks pregnant 25 — the recommended total gain, low is 11.5 kg. Put your own figures in their place and the working updates beside the result.
Which trimester is the most weight gain?
It needs Units, Pre-pregnancy weight, Height, Pre-pregnancy BMI (optional), Weeks pregnant and Current weight. Nothing else is required, and the figures stay in your browser.
How to slow down pregnancy weight gain?
Works out the recommended total and week-by-week gestational weight gain from pre-pregnancy BMI using the 2009 IOM/NRC guidelines, and compares it with the weight gained so far. Open “How this is worked out” beside the result to see each step for your own figures.
What information do I need for the Pregnancy Weight Gain Calculator?
You need Units, Pre-pregnancy weight, Height, Pre-pregnancy BMI (optional), Weeks pregnant, Current weight and Number of babies. The page opens with default figures that give recommended total gain, low of 11.5 kg, so you can see the scale before entering your own.
What does this Pregnancy Weight Gain Calculator show?
It shows Pre-pregnancy BMI, BMI category, Recommended total gain, low, Recommended total gain, high, Recommended gain by this week, low, Recommended gain by this week, high, Weekly rate from week 14, low and Weekly rate from week 14, high, with the working and any warnings for your entries.