Pregnancy Due Date Calculator
Enter your dates below to get your estimated due date, gestational age, trimester, and key milestone dates. Results update instantly.
Last reviewed: June 2026This calculator estimates dates only. A healthcare provider or midwife should confirm dating, interpret ultrasound results, and guide prenatal care.
Key Pregnancy Milestones
Enter your dates above to populate estimated milestone dates.
| Week | Milestone | Est. Date | Status |
|---|---|---|---|
| Enter a date above to see milestone dates. | |||
How the Pregnancy Due Date Calculator Works
This calculator estimates an expected due date from one of three inputs: the first day of the last menstrual period, an IVF embryo transfer date, or an estimated conception date. It also back-calculates gestational age, trimester, days remaining, and milestone dates from the same estimated timeline.
LMP Method
For a 28-day menstrual cycle, the calculator adds 280 days to the first day of the last menstrual period. If you enter a cycle length other than 28 days, it shifts the due date by the difference. For example, an LMP date of January 1, 2026 with a 28-day cycle estimates a due date of October 8, 2026. A 35-day cycle moves that estimate to October 15, 2026.
IVF and Conception Methods
The IVF tab uses the embryo transfer date and transfer day. A day-5 transfer adds 261 days; a day-3 transfer adds 263 days. The conception tab assumes an LMP-equivalent date 14 days before the conception date, then adds 280 days. These are date-estimation shortcuts, not diagnostic tests.
What the Result Can and Cannot Tell You
The output is useful for calendar planning and understanding common prenatal milestones. It cannot confirm pregnancy, assess fetal growth, determine fetal sex, diagnose complications, or decide whether a pregnancy is progressing normally. Early ultrasound dating and clinical history can be more accurate than LMP alone, especially when cycles are irregular or the LMP date is uncertain.
Source Notes
ACOG Committee Opinion No. 700, Methods for Estimating the Due Date, reaffirmed in 2025, says the estimated due date should be determined once LMP and the first accurate ultrasound information are available, discussed with the patient, and documented clearly. The SMFM publication page summarizes the same guidance.