Estimate your pregnancy due date from the first
day of your last menstrual period (LMP).
You can also adjust the calculation for your
usual menstrual cycle length.
Select the first day of your last menstrual
period, not the last day.
The standard calculation assumes a 28-day
cycle. Enter your usual cycle length if known.
Please enter valid information.
Pregnancy Date Estimate
Estimated Due Date
-
LMP Date
-
Cycle Length
-
Estimated Conception
-
Estimated Pregnancy Milestones
These dates are calculated from the same
LMP-based pregnancy timeline and are
approximate.
12 Weeks
-
20 Weeks
-
28 Weeks
-
37 Weeks
-
40 Weeks
-
Standard pregnancy dating is approximately:
40 weeks (280 days) from LMP
How is the due date calculated?
Pregnancy is conventionally dated from the
first day of the last menstrual period,
even though conception usually occurs later.
Standard Estimated Due Date
= LMP + 280 days
A 28-day menstrual cycle is normally assumed.
If your usual cycle is longer or shorter,
this calculator adjusts the estimate by the
difference.
Adjusted Due Date =
LMP + 280 days
+ (Cycle Length - 28 days)
For example, a 30-day cycle adds:
30 - 28 = 2 days
Adjusted Due Date =
Standard Due Date + 2 days
Important:
This calculator provides an estimate only.
The actual date of conception and delivery
can differ from an LMP-based estimate,
especially when cycles are irregular or the
LMP is uncertain. Clinical pregnancy dating,
including ultrasound when appropriate, may
revise the estimated due date. Use the due
date provided by your maternity healthcare
professional for medical decisions and care
planning.
