My cycle isn't 28 days. Does it matter?

A bit. Naegele's rule assumes a 28-day cycle with ovulation on day 14. If your cycle is regularly longer/shorter, your real due date shifts by the same amount — your doctor will adjust based on first-trimester ultrasound.

Can the calculator predict baby's sex?

No, and don't trust any tool that claims to from a date. Sex is determined at conception by sperm chromosome and isn't deducible from due date math.

Pregnancy Due Date Calculator

Estimated due date from last menstrual period, conception date, or IVF transfer date.

Result

Estimated due date

Wed, 06 Jan 2027

246 days from today

Current pregnancy week4 weeks 5 days
TrimesterFirst trimesterNote
Days since start event33
Estimated conception dateWed, 15 Apr 2026
Method usedNaegele's rule (LMP + 280 d)

How to use this calculator

LMP is the most common method — pick the first day of your last period.
IVF transfer dates: be sure whether your transfer was 3-day or 5-day embryo (your clinic told you).
Conception dates are only reliable if you have ovulation tracking (BBT or LH strips).
Always confirm with your doctor — first-trimester ultrasound dating is more accurate.

About this tool

A pregnancy lasts about 40 weeks counted from the first day of the last menstrual period — a calculation called Naegele's rule, used since the 19th century. If you know the conception date instead (often the case after IVF or with carefully tracked cycles), the math shifts by 14 days. Only about 5 % of babies arrive on the exact predicted day; "term" is anywhere from 37 to 42 weeks. The due date is mainly a planning anchor for prenatal appointments, not a deadline. An ultrasound between weeks 8 and 14 gives a more accurate date than LMP alone.

Frequently asked

About ±2 weeks for the actual delivery — only 5 % of babies are born on the exact date. First-trimester ultrasound dating is the gold standard; LMP-based dates can be off by up to 2 weeks if cycles are irregular.