Updated Conception & Pregnancy

Conception Calculator

Estimate likely conception date, due date, ovulation day, fertile window, orerse conception from due date or birth date.

Ovulation & Fertile Window Due Date Estimate Reverse Conception Informational Only

All-in-One Conception & Pregnancy Timing Tool

Switch between LMP-based due date, ovulation & fertile window, anderse conception estimation.

This tool uses standard assumptions (28-day cycle, ovulation around 14 days before the next period) and provides only approximate dates. Always confirm dates with a qualified healthcare professional.
Ovulation and fertile window estimates are based on cycle averages and may vary from person to person. For medical or fertility planning, speak with your doctor or fertility specialist.
erse conception calculations are approximate and cannot determine the exact day of conception or exclude other possible dates. For legal, medical, orationship questions, consult a professional.

Conception Calculator – Ovulation, Due Date &erse Conception

This Conception Calculator brings together three popular tools in one place: a due date and conception estimator based on LMP, an ovulation and fertile window calculator, and aerse conception tool that works from a known due date or birth date.

1. Conception & Due Date from LMP

When you enter the first day of your last menstrual period (LMP) and your average cycle length, the calculator:

  • Estimates your likely conception date based on ovulation timing
  • Calculates an approximate due date using a standard 40-week pregnancy model
  • Shows your current gestational age in weeks and days, based on today’s date

By default, the tool assumes ovulation happens 14 days before your next expected period. Longer or shorter cycles shift that ovulation day earlier or later.

2. Ovulation & Fertile Window Calculator

If you are trying to conceive, the ovulation tab focuses on your most fertile days. With your LMP and cycle length, it estimates:

  • Your next likely ovulation date
  • A fertile window of several days leading up to ovulation and shortly afterward
  • Your expected next period based on cycle length

Because sperm can survive in the reproductive tract for several days, intercourse before ovulation can still result in pregnancy, which is why a multi-day fertile window is shown instead of just one day.

3.erse Conception from Due Date or Birth Date

Theerse conception mode is for users who already know a due date or birth date and want to estimate when conception most likely occurred. It uses common clinical assumptions:

  • Due date ≈ conception date + 266 days
  • Due date ≈ LMP + 280 days (40 weeks)

From those assumptions, the calculator estimates:

  • A likely conception date
  • A small conception window, a few days around that estimate
  • An approximate LMP date

Important Limitations

Every body and every pregnancy is different. Ovulation can happen earlier or later than expected, cycles may vary from month to month, and babies rarely arrive exactly on their calculated due date. Ultrasound measurements and medical examinations usually provide more accurate dating than any online calculator.

This conception calculator is for general information and education only. It does not provide medical advice, diagnosis, or treatment, and it cannot determine exact dates of conception. Always talk to a doctor, midwife, or other qualified healthcare professional questionsated to pregnancy, fertility, or your personal health.

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