Pregnancy Due Date Calculator

Estimate your baby’s due date (EDD), fetal age, and key pregnancy milestones using your last menstrual period, conception date, ultrasound, or IVF transfer date.

Our calculator provides a detailed pregnancy timeline, including trimester breakdowns, developmental stages, and critical dates to guide you through your pregnancy journey. Always consult a healthcare professional for personalized medical advice.

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Tool Input

Please select a valid date not in the future.
Please enter a cycle length between 21 and 45 days.
Typically 28 days
Please select a valid date not in the future.
Please enter weeks between 1 and 40.
Please enter days between 0 and 6.
Please select a valid date not in the future.
Please select a valid date not in the future.
Please select a transfer type.

Results

Your pregnancy results will appear here after calculation

Pregnancy Milestones

Calculate your due date to see important pregnancy milestones.

How This Pregnancy Calculator Works

Our calculator estimates your due date and pregnancy milestones using one of four methods. Always confirm with a healthcare provider, as individual factors may vary.

Last Menstrual Period (LMP) Method

Calculates the due date by adding 280 days (40 weeks) from the first day of your last period, adjusting for cycle length. This assumes ovulation occurs around day 14 for a 28-day cycle.

Ultrasound Dating

Uses the ultrasound date and gestational age (weeks and days) to back-calculate the conception date, then adds 280 days for the due date. First-trimester ultrasounds are most accurate (±5–7 days).

Conception Date

Adds 266 days (38 weeks) to the known conception date, ideal for those with precise conception timing (e.g., fertility treatments).

IVF Transfer Date

Calculates the due date by adding 266 days minus the embryo age (e.g., 5 days for a Day 5 blastocyst) from the transfer date. For Day 5 embryos, this is 261 days from transfer.

Pregnancy FAQs

How accurate is the due date calculation?

Only about 5% of babies are born on their exact due date. Most deliver within two weeks before or after. First-trimester ultrasounds are the most accurate, with a margin of ±5–7 days, while LMP-based estimates vary based on cycle regularity.

Adjust the cycle length in the LMP method to account for longer or shorter cycles. Ovulation typically occurs 14 days before your next period, so a longer cycle delays ovulation and conception, affecting the due date.

Gestational age starts from the first day of your last period, while fetal age begins at conception (about two weeks later). Gestational age is used by healthcare providers to track pregnancy progress.

First trimester: Weeks 1–12 (embryo development, organ formation)

Second trimester: Weeks 13–26 (fetal growth, movement felt)

Third trimester: Weeks 27–birth (rapid growth, preparation for delivery)

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