Pregnancy Conception Calculator
Estimate your conception date and fertile window from the first day of your last menstrual period.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Your result
15-06-2026
Estimated conception date
AI explanation
Formula
Estimated conception = last period date + 14 days, assuming a standard 28-day cycleWorked example
LMP 2026-01-01
| Field | Value |
|---|---|
| First day of last menstrual period | 01-01-2026 |
| Estimated conception date | 15-01-2026 |
Assumptions
- Assumes ovulation (and conception) occurs around day 14 of a standard 28-day cycle — actual timing varies with individual cycle length.
- The conception window spans a few days either side of the estimated ovulation date, since sperm can survive several days and the egg is viable for roughly 24 hours.
- Informational only.
Frequently asked questions
How is conception date estimated?
Assuming a standard 28-day cycle, ovulation (and likely conception) occurs around day 14 after the start of the last menstrual period.
Why is this only an estimate?
Actual ovulation timing depends on your individual cycle length, which can vary from the standard 28-day assumption — the Ovulation Calculator lets you enter your own cycle length for a more personalized estimate.
Is conception the same day as ovulation?
Conception can occur within about a day of ovulation, since sperm can survive in the reproductive tract for several days before the egg is released.
Related calculators
Sources
- Methods for Estimating the Due Date — American College of Obstetricians and Gynecologists (ACOG). Effective 01-05-2017, reviewed 13-09-2026.
This calculator provides a general estimate only and does not constitute personalized medical advice.
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