Due Date Calculator

Calculate your pregnancy due date from LMP or conception date

Wondering when your baby is due? Our due date calculator gives you an instant estimate of your delivery date based on either your last menstrual period (LMP) or your conception date, using the same method most doctors and midwives use.

While only about 5% of babies are actually born on their exact due date, knowing your estimated due date (EDD) helps you track pregnancy milestones, plan prenatal visits, and prepare for your baby's arrival with confidence.

How This Calculator Works

This calculator uses Naegele's Rule, the standard clinical formula for estimating due dates. If you calculate by LMP, it adds 280 days (40 weeks) to the first day of your last period, adjusted for your average cycle length. If you calculate by conception date, it adds 266 days (38 weeks), since conception typically occurs around two weeks after the start of your cycle.

Simply choose your preferred method, enter the date, and for the LMP method, your average cycle length (the calculator defaults to a standard 28-day cycle but adjusts for shorter or longer cycles).

Why Use This Calculator

  • Get an instant, doctor-style due date estimate in seconds
  • See your current week and day of pregnancy at a glance
  • Know exactly how many days remain until your due date
  • Plan prenatal appointments, baby showers, and maternity leave with a clear timeline

Frequently Asked Questions

Due date calculators give a reliable estimate, not a guarantee. Most babies are born anywhere between 37 and 42 weeks of pregnancy, so your due date is best thought of as the midpoint of a five-week window rather than an exact day.

If you know your exact conception date (for example, from IVF or ovulation tracking), it tends to be slightly more precise than LMP, since LMP calculations assume a textbook 28-day cycle unless you adjust it.

If your cycles are irregular, the LMP method becomes less reliable. In that case, an early ultrasound dating scan (usually done between 8–13 weeks) is the most accurate way to confirm your due date.

Yes. Your doctor may adjust your due date after your first ultrasound, which measures the baby directly and is generally considered more accurate than calendar-based methods, especially if your cycle isn't a standard 28 days.

Full term is considered 39 to 40 weeks. Babies born between 37–38 weeks are called 'early term,' and those born after 42 weeks are considered 'post-term.'
This tool provides an estimate for informational purposes only and is not a substitute for medical advice. Always confirm your due date with your doctor or midwife.
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