Pregnancy Due Date Calculator

Pregnancy Calculator

Find Your Due Date

Estimate your delivery date and see exactly where you are in your pregnancy — from your last period, conception date, IVF transfer, ultrasound, or a due date you already have.

Due date calculator

Most cycles run 21–35 days. Leave this at 28 if you’re not sure.

This tool provides an estimate using standard clinical formulas. It isn’t a medical diagnosis — always confirm your due date with your healthcare provider.

How Your Due Date Is Calculated

Last Menstrual Period

The most common starting point. Your due date is set 280 days from the first day of your last period, adjusted slightly if your average cycle runs longer or shorter than 28 days.

Conception Date

If you know roughly when you conceived — through ovulation tracking or a fertility monitor — your due date is set 266 days from that date. Often more precise for irregular cycles.

IVF Transfer

The embryo transfer date is known exactly, making this the most precise method. Count forward 263 days for a day-3 transfer, 261 for day-5, or 260 for day-6.

Ultrasound

An early scan measures the fetus directly to estimate gestational age — often the most reliable option if your cycle is irregular or your last period date is uncertain.

Known Due Date

Already have a due date from your doctor? Enter it directly and this tool works backward to estimate your conception date and full week-by-week timeline.

Common Questions

How accurate is my due date?+

Due dates are estimates, not guarantees — only around 1 in 20 babies arrive on their exact due date. Most healthy pregnancies deliver between 37 and 42 weeks, so it helps to think of your due date as the middle of a range rather than a fixed deadline.

What if I don’t know my last period date?+

If your cycles are irregular or you’re unsure of your last period, a first-trimester ultrasound is generally the most reliable way to date a pregnancy. Early scans measure the fetus directly, which tends to be more accurate than calendar-based methods when cycle history is unclear.

Can my due date change during pregnancy?+

Yes. It’s common for a due date to be adjusted after an early ultrasound, especially if the scan suggests a different gestational age than the calendar method did, or if your cycle is notably longer or shorter than the standard 28 days.

How many weeks pregnant am I today?+

Pregnancy is dated from the first day of your last period, not the day of conception — so by convention you’re considered about two weeks pregnant before conception actually happens. This is the standard used by healthcare providers to keep dating consistent from one appointment to the next.

This calculator is for informational purposes only and does not replace medical advice. Always consult your healthcare provider to confirm your due date and discuss your care.