Pregnancy Due Date Calculator

Uses Naegele’s Rule, adjusted for cycle length, to calculate the Estimated Due Date (EDD) and current gestational age.

Last Menstrual Period (LMP)

Average Cycle Length

days

Estimated Due Date

–

Gestational Age (EGA): –
Estimated Conception Date: –
Days Remaining: –

First Trimester Ultrasound: If the crown-rump length (CRL) dating differs from LMP dating by >7 days in the first trimester, the ultrasound date is considered the gold standard.

Cycle Variability: This formula assumes ovulation occurs exactly 14 days before the next period. Irregular cycles make LMP dating less reliable.

Naegele’s Rule: Standard calculation is LMP + 9 months + 7 days. Our tool specifically adjusts this based on cycle length variations.

Pregnancy Due Date Calculator (EDD)