Pregnancy Due Date Calculator — LMP, Conception & IVF

Estimate your baby's due date from your last menstrual period (Naegele's rule), your conception date, or your IVF embryo transfer date. See how many weeks pregnant you are, your trimester, and key milestones.

How to use the Pregnancy Due Date Calculator

  1. Choose a Method: Go to fixflowhub.com/pregnancy-due-date-calculator and choose Last Period, Conception, or IVF Transfer
  2. Enter Your Date: Enter the relevant date (and cycle length or embryo age if asked)
  3. View Results: See your estimated due date, current week, and trimester

Frequently Asked Questions

How to calculate pregnancy due date online?

Go to fixflowhub.com/pregnancy-due-date-calculator, enter the first day of your last menstrual period, and get your estimated due date instantly. Free.

How is the due date formula calculated?

The standard estimate adds 280 days (40 weeks) to the first day of your last menstrual period (Naegele's rule). This is an estimate — your healthcare provider may adjust it based on ultrasound measurements.

How accurate is a due date estimate?

Only about 5% of babies are born on their exact estimated due date. Most healthy deliveries occur anywhere between weeks 37 and 42, so treat the date as a general planning window rather than a fixed deadline.

How is an IVF due date calculated?

For IVF pregnancies the due date is calculated from the embryo transfer date: add 261 days for a Day 5 (blastocyst) transfer, or 263 days for a Day 3 transfer.

Should I rely on this instead of my doctor's estimate?

No — this tool provides a quick estimate for planning purposes only. Always follow the due date and prenatal guidance given by your healthcare provider, who can factor in ultrasound dating and your individual pregnancy details.

Related free tools

More free calculators