Pregnancy Due Date Calculator | Estimated Timeline

Estimate pregnancy due date, current week, trimester, and key timeline dates from last menstrual period and average cycle length.

First Day of Last Menstrual Period

📅

Average Cycle Length (days)

🔁

Estimated Pregnancy Timeline

Estimated Due Date

Estimated Pregnancy Week

Estimated Trimester

End of First Trimester

End of Second Trimester

Full-Term Starts

Estimate Pregnancy Due Date from LMP

Enter the first day of the last menstrual period and average cycle length to estimate due date, current pregnancy week, trimester, and full-term timing.

Due Dates Are Medical Estimates

Cycle length, ovulation timing, ultrasound dating, and medical history can change the official due date. Confirm pregnancy dates with a qualified healthcare professional.

Frequently Asked Questions

How accurate is an LMP-based due date?

The LMP method assumes a 28-day cycle and ovulation on day 14. A first-trimester ultrasound provides a more accurate estimate based on foetal measurements.

How many weeks is a full-term pregnancy?

A full-term pregnancy is 39 to 40 weeks from the last menstrual period. Births between 37 and 42 weeks are considered term.

What is Naegele's rule?

Naegele's rule calculates the due date by adding one year, subtracting three months, and adding seven days to the first day of the last period — equivalent to adding 280 days.

About This Tool

Due Date Calculator estimates a pregnancy due date from the first day of the last menstrual period or from a known conception date. It also shows key pregnancy milestones and trimester boundaries week by week.

When to Use It

Use this after a positive pregnancy test to estimate the due date before the first ultrasound, when planning maternity leave around an expected delivery, or when tracking weekly pregnancy milestones.

Step by Step

Enter the first day of your last menstrual period.
Alternatively enter a known conception date.
Click Calculate to see the estimated due date.
Review the trimester timeline and key milestones by week.

You Might Also Need

Age Calculator Date Calculator Ovulation Calculator