Pregnancy Conception Calculator
Estimate conception timing from LMP, due date, or gestational age.
This page is an editable estimator with realistic defaults so you can model your own situation in minutes.
Estimated conception is about 14 days after LMP for a 28-day cycle, or 266 days before due date.
Treat the result as a planning estimate and verify important numbers with the relevant official source before acting.
| Reference method | dueDate | |
|---|---|---|
| Cycle length | 28 days |
Assumptions
- Conception timing is an estimate, not proof of the exact date.
- Clinical dating may rely on ultrasound and medical history.
How this calculator works
Formula used
Estimated conception is about 14 days after LMP for a 28-day cycle, or 266 days before due date.
Example calculation
Plug in your own numbers and the result updates instantly. Estimated conception is about 14 days after LMP for a 28-day cycle, or 266 days before due date.
Pregnancy Conception Calculator FAQ
Is this pregnancy conception calculator medical advice?
No. It is an educational estimate only and does not replace an OB-GYN, midwife, fertility specialist, pediatric clinician, or emergency care.
Why might my actual dates or recommendations differ?
Cycle length, ovulation timing, ultrasound dating, implantation timing, multiples, medical history, and clinician judgment can change pregnancy and fertility estimates.
Should I confirm results with a clinician?
Yes. Confirm pregnancy dating, weight gain, cycle concerns, fertility timing, or health decisions with a qualified healthcare professional.