Fitness & Health

Due Date Calculator

Calculate pregnancy due date from last period, conception date, or IVF transfer date.

Inputs

Results update as you edit.

Dating method

Known date

Estimated due date

Nov 6, 2026

Results update as the calculator inputs change.

This is an estimate only and is not medical advice.

First trimester ends

May 8, 2026

Second trimester ends

Aug 7, 2026

Full-term window begins

Oct 16, 2026

Full-term window ends

Nov 13, 2026

How to Calculate a Due Date

Dating Method

The estimate can start from last period, conception date, or IVF transfer date.

Gestational Age

Pregnancy dating is counted in weeks and days from the selected reference point.

Clinical Confirmation

Providers may update the official date using early ultrasound and clinical guidance.

How Due Date Methods Differ

Due-date calculators use standard pregnancy dating assumptions. The best estimate depends on the quality of the input date and whether a clinician has confirmed dating with ultrasound.

What Affects Due Date Accuracy?

Input Date

LMP, conception, and transfer dates use different offsets.

Cycle Regularity

Irregular cycles can make LMP-based dating less precise.

Ovulation Timing

Ovulation timing affects conception-based estimates.

IVF Details

Transfer day changes the offset used for IVF dating.

Ultrasound Timing

Early ultrasound is often more useful for dating than later scans.

Provider Guidance

The documented clinical due date should guide care.

Common Due Date Inputs

Last Period

Estimate from the first day of the last menstrual period.

Conception Date

Estimate from a known or assumed conception date.

IVF Transfer

Estimate from embryo transfer timing when relevant.

Frequently Asked Questions

Which due date method is best?

The best method depends on your situation. A clinician may use LMP, ultrasound, conception information, or IVF details.

Why is pregnancy counted from the last period?

Gestational age traditionally starts from LMP, which is often easier to identify than conception.

Can my due date change?

Yes. Your provider may revise it if ultrasound or clinical information supports a different estimate.

Do most babies arrive on the due date?

No. The due date is an estimate, and many births happen before or after it.

Is this medical advice?

No. Use it for planning and rely on your obstetric care team for clinical decisions.