How to use pregnancy & fertility date calculators
Date-based pregnancy and fertility tools are helpful for planning, but individual cycle timing varies. Use these results as estimates and confirm important dates and medical decisions with your prenatal care team.
Due date (EDD): LMP vs conception date
- LMP is the most common clinical method: it dates pregnancy from the first day of the last menstrual period.
- Conception date can be useful if you track ovulation or have IVF timing.
Ovulation and cycle tracking
Ovulation calculators assume typical timing based on cycle length. If your cycles are irregular, treat results as a planning range rather than a single exact day.
Related tools
Pregnancy calculators FAQ
Q:Are due date calculators exact?
No—an EDD is an estimate. Only a small percentage of births occur exactly on the due date, and early ultrasound can refine dating when LMP is uncertain.
Q:Can I use these tools if my cycle is irregular?
Yes, but interpret results as a range. Irregular cycles can shift ovulation timing, which affects conception and due-date estimates.