Pregnancy Due Date Calculator

Quick Presets:

Input Parameters

First Day of Last Period (LMP)

The first day of bleeding in your last period.

Average Menstrual Cycle Length

20d (Short) 28d (Standard) 45d (Long)

Luteal Phase Duration

Time between ovulation and your next cycle (typically 14 days).

Pregnancy History (Parity)

First pregnancies average 8 days longer under clinical research.

Exact Conception / Ovulation Date

Exact ovulation or conception date (+266 days to EDD).

Pregnancy History (Parity)

IVF Transfer Date

Embryo Stage at Transfer

Day 5 Blastocyst

Standard (261d)

Day 3 Embryo

Cleavage (263d)

Day 6 Blastocyst

Extended (260d)

Egg Retrieval

Day 0 (266d)

Ultrasound Scan Date

Gestational Age at Scan

wks

days

From CRL (crown-rump length) ultrasound report.

Assigned Due Date (EDD)

Reverse calculates your conception date, LMP, and full 40-week milestone timeline.

Multiplicity

Units

Estimated Due Date (EDD)

• Conception: • LMP:

Pregnancy Progress ( completed) 40 Weeks Total

1st Trimester (1–13w) 2nd Trimester (14–27w) 3rd Trimester (28–40w+)

Gestational Age

Trimester

Baby Size

Baby Zodiac

1st Trimester Wks 1–13

Heartbeat forms, organogenesis.

2nd Trimester Wks 14–27

Anatomy scan, movements felt, 24w viability.

3rd Trimester Wks 28–40+

Rapid brain/lung growth, full term.

Formula Rule	Estimated Due Date	Variance
Naegele's Rule (LMP + 280d)		Baseline
Parikh's Formula (Cycle Adjusted)
Mittendorf-Williams Rule ()
French Rule / Pinard (LMP + 283d)		+3d

ACOG & NHS Recommended Milestones

Week-by-Week Growth Scrubber

Len: Wt:

Milestone:

Tip:

Preterm (< 37 Weeks) ~10%

10%

Early Term (37–38 Weeks) ~26%

26%

Full Term Window (39–40 Weeks) — Peak ~57%

57%

Late Term (41 Weeks) ~6%

6%

💎

Calculators

Pregnancy Due Date Calculator

Accurately calculate your estimated due date (EDD), track your pregnancy progress week-by-week, and explore essential prenatal milestones. Supports calculations via Last Menstrual Period (LMP) with cycle length adjustment, precise Conception Date, IVF Transfer (Day 3, Day 5 blastocyst, Day 6, or egg retrieval), Ultrasound Dating Scan, and reverse Due Date calculations. Features baby fruit size comparisons, trimester breakdowns, prenatal clinical test schedules, delivery probability curves, and one-click calendar export (.ics).

Multi-Method Calculation Week-by-Week Fetal Growth Prenatal Clinical Timeline Apple & Google iCal Export

Did You Know?

Due Date Reality: Only about 4% to 5% of babies are born on their exact estimated due date. Most healthy babies arrive in the "term window" between 37 weeks and 41 weeks, 6 days. Your due date serves as an essential compass for prenatal care and developmental milestones!

Pregnancy Due Date Calculator

Pregnancy Due Date Calculator

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