Antpact Toolbox
中文
Home › Calculators › Due Date Calculator

Due Date Calculator

Estimate due date and current pregnancy week from LMP.

Privacy: this tool runs entirely in your browser — files are never uploaded, and data is gone when you close the page.

How to use

  1. Enter LMP date.
  2. See estimated due date and week.
  3. Confirm with your doctor.

FAQ

Is the due date exact?

It is an estimate; only about 5% of babies arrive on that day, and delivery within two weeks either side is normal. Follow your doctor.

How is the week counted?

From the first day of LMP, 7 days per week, for a full term of about 40 weeks (280 days).

I don't remember my LMP — what then?

An early ultrasound (gestational sac or CRL) can back-calculate the week more accurately; this tool estimates from LMP and can be corrected with the scan.

How do I see how many weeks pregnant I am now?

Enter your LMP and set today as the end date; the tool shows the current week and days remaining.

Past the due date and not delivered?

Up to two weeks over is common; doctors usually assess induction after that. Keep your prenatal checkups.

Ovulation is ~2 weeks after LMP — do I add it?

Naegele's rule already bakes in the ~2-week ovulation offset from LMP, so do not add two weeks yourself.

About this Due Date Calculator

Uses Naegele's rule: due date = LMP + 280 days. Week is estimated from today. Reference only.