How to Use the Pregnancy Weeks and Months Calculator
Doctors talk in weeks, but everyday conversations often use months, which can get confusing. Enter the first day of your last period and this tool instantly shows your current pregnancy week, month, and estimated due date.
How Weeks and Months Are Calculated
Dividing the days since your last period by 7 gives the current week — the standard method used in obstetrics. Months are shown using a 4-week-per-month convention, for a total of 10 months (40 weeks).
How the Due Date Is Estimated
The estimated due date is your last period date plus 280 days (40 weeks). Actual delivery dates vary by person, so always confirm the precise due date with your doctor.
Frequently Asked Questions
How is pregnancy week calculated?
Days since your last period divided by 7 — the standard method used by clinics.
How is the due date determined?
Your last period date plus 280 days. Actual dates vary by person.