Enter your LMP to calculate your pregnancy timeline.
The Last Menstrual Period, or LMP, is the first day of your most recent menstrual cycle. Doctors and midwives use this date to estimate how far along a pregnancy is and to predict an approximate due date. Even though conception usually happens around two weeks after the LMP, this date remains the most reliable reference point for early pregnancy calculations because it is easier to identify compared to ovulation day.
By entering the first day of your LMP, the calculator estimates your gestational age, how many weeks pregnant you are today, and your expected due date based on the standard 40-week pregnancy model. This is useful for moms who want to track their pregnancy timeline before visiting a clinic or simply want a quick guide for monitoring symptoms and planning ahead.
The due date is calculated as 280 days (40 weeks) from the LMP. While it is only an estimate—since every pregnancy is unique—it provides a strong baseline for planning prenatal checkups, monitoring fetal development, and preparing for childbirth. Most babies do not arrive exactly on their due date, but the LMP method remains a widely accepted and helpful tool for estimating.
Ultrasound scans can offer highly accurate measurements, especially in the first trimester, but LMP is still used because it establishes an early timeline for your pregnancy. Doctors often compare LMP-based dates with ultrasound results and adjust the due date if needed. Both pieces of information work together to track your pregnancy as accurately as possible.
If you have irregular cycles, very light periods, or uncertainty about the exact date of your last period, your estimated pregnancy age may differ slightly. This is normal. A dating ultrasound can provide a clearer estimate, but the LMP calculator still serves as a helpful starting point for understanding your current pregnancy stage.
This calculator provides general estimates only and is not a substitute for medical advice. For accurate pregnancy dating and personalized guidance, consult your OB-GYN or midwife.