Compare calculators
Both calculators run independently β change the inputs on either side to compare results.
Pregnancy
Baby Size Calculator
Estimates fetal weight and size using gestational age alone or ultrasound measurements (BPD, FL, AC). Used by parents and clinicians to track growth against standard developmental charts.
Fill in the required fields to see your result.
Pregnancy
Due Date Calculator
Estimates your baby's due date by adding 280 days (40 weeks) to the first day of your last menstrual period (LMP) using Naegele's Rule. Use it in early pregnancy to plan prenatal appointments, milestones, and parental leave.
Fill in the required fields to see your result.
Key differences
| Baby Size Calculator | Due Date Calculator | |
|---|---|---|
| Category | Pregnancy | Pregnancy |
| Inputs required | 5 | 1 |
| Result | Estimated Baby Weight (grams) | Days until due date (days) |
| What it does | Estimates fetal weight and size using gestational age alone or ultrasound measurements (BPD, FL, AC). Used by parents and clinicians to track growth against standard developmental charts. | Estimates your baby's due date by adding 280 days (40 weeks) to the first day of your last menstrual period (LMP) using Naegele's Rule. Use it in early pregnancy to plan prenatal appointments, milestones, and parental leave. |