Enter Pregnancy Details
The page uses a single-column structure, while the calculator fields switch to 3, 2, or 1 columns by screen size.
Plotly Graph
The chart compares your current gain, projected full-term gain, and the recommended total range.
Example Data Table
| Pregnancy Type | Week | Height | Pre Weight | Current Weight | Pre BMI | Category | Gain | Recommended Gain |
|---|---|---|---|---|---|---|---|---|
| Singleton | 28 | 165 cm | 60.0 kg | 67.5 kg | 22.04 | Healthy Weight | 7.5 kg | 11.34 to 15.88 kg |
| Twins | 30 | 168 cm | 70.0 kg | 81.0 kg | 24.80 | Healthy Weight | 11.0 kg | 16.78 to 24.49 kg |
Formula Used
BMI = weight (kg) ÷ height² (m²)
BMI = [weight (lb) ÷ height² (in²)] × 703
Current Gain = Current Weight − Pre-pregnancy Weight
Average Weekly Gain = Current Gain ÷ Gestational Week
Projected Gain = Average Weekly Gain × Term Week
Remaining = Recommended Limit − Current Gain
Recommended total gain is selected from the pre-pregnancy BMI category and pregnancy type. Guidance should be reviewed with a qualified prenatal clinician.
How to Use This Calculator
- Select metric or imperial units.
- Choose singleton or twins.
- Enter gestational week.
- Enter height and pre-pregnancy weight.
- Enter your current weight.
- Press Calculate.
- Review BMI category, current gain, projection, and target range.
- Download the summary as CSV or PDF if needed.
Frequently Asked Questions
1. What does this calculator estimate?
It estimates pre-pregnancy BMI, current BMI, current pregnancy weight gain, recommended total gain range, average weekly gain, and a simple full-term projection.
2. Why is pre-pregnancy BMI used?
Pregnancy weight-gain guidance is usually based on the BMI before pregnancy began. That category helps determine the recommended total gain range.
3. Does the current BMI change the recommendation?
No. The recommendation shown here is based on pre-pregnancy BMI. Current BMI is displayed only as a reference value.
4. Can I use this for twins?
Yes. The tool includes a twins option and adjusts the recommended total gain band. Twin pregnancies often need closer clinical review.
5. What does projected total gain mean?
It extends your average gain so far to the selected term week. It is a pacing estimate, not a diagnosis or treatment target.
6. What if my current gain is negative?
The calculator can still show the math, but continued weight loss in pregnancy should be discussed with a clinician, especially with vomiting or poor intake.
7. Are BMI results perfect during pregnancy?
No. BMI is a screening tool, not a complete measure of health. Pregnancy symptoms, edema, body composition, and medical conditions can affect interpretation.
8. Should this replace prenatal care advice?
No. Use it as an educational tracker. Personal recommendations can differ based on medical history, blood pressure, glucose status, fetal growth, and clinician judgment.