Due Date Calculator
Due Date Estimator
Results
| Estimated Due Date | — |
|---|---|
| Conception Date | — |
| Gestational Age | — |
| Trimester | — |
Pregnancy Due Date Milestones
Your due date represents 40 weeks (280 days) from the first day of your last menstrual period (LMP) or 266 days from fertilization (conception). It is a guideline; only about 4-5% of babies are born exactly on their estimated due date.
How Due Dates Are Determined
- Last Menstrual Period (LMP): Computed by adding 280 days to the start of the last period, adjusted if your average cycle is shorter or longer than the standard 28 days.
- Ultrasound scan: In early pregnancy, an ultrasound scan measuring the crown-rump length is the most accurate way to date a pregnancy. It overrides dates calculated from periods if they differ by more than 5-7 days.
- IVF Transfer: In-vitro fertilization transfers have a precise conception age. For a 3-day embryo, due date is 263 days from transfer. For a 5-day blastocyst, due date is 261 days from transfer.
Disclaimer. This calculator is informational only and does not substitute for professional medical advice. Individual pregnancies differ; consult a healthcare provider for clinical dating and prenatal care.