Ovulation
estimated ovulation = LMP + (cycle length - 14 days)
Pregnancy Week Calculator
Calculate your current pregnancy week and estimated due date from your last menstrual period or conception date.
Women's Health & Pregnancy
Life Cycle Management
Track ovulation, fertile window, and due date based on your LMP.
Estimated Ovulation
October 4, 2026
Fertile Window
October 1, 2026 ~ October 5, 2026
Due Date
June 27, 2027
* 이 계산기는 통계적 평균치를 기반으로 하며, 실제 주기는 개인의 컨디션에 따라 다를 수 있으므로 참고용으로만 사용하시기 바랍니다.
Pregnancy dating often starts from the first day of the last menstrual period
This calculator uses last menstrual period (LMP) and average cycle length to estimate ovulation, fertile window, and due date. The due date is calculated by adding 280 days to LMP, a common clinical convention, but ultrasound and clinical history may adjust dating.
Calculation basics
Fertile window
from 3 days before ovulation through 1 day after
Due date
estimated due date = LMP + 280 days
How to use
- Enter the first day of the last menstrual period.
- Enter average cycle length in days.
- Review ovulation, fertile window, and estimated due date as planning references.
Frequently asked questions
Is the due date exact?
No. It is a statistical estimate; actual delivery commonly occurs before or after the date.
What if cycles are irregular?
LMP-based dating can be less reliable. Ultrasound dating and clinician review become more important.
Can this be used for contraception or fertility decisions?
Not by itself. Ovulation can shift with stress, illness, sleep, medication, and individual variation.
Results are general estimates and are not a substitute for professional obstetric medical advice, diagnosis, or care.