Work out when conception happened, or when it can

All calculators

• Conception Date Calculator

  Find the most likely conception date from your due date.

• Conception Calculator by Birth Date

  Estimate when someone was conceived from their date of birth.

• Due Date Calculator

  Estimate your due date from the first day of your last period.

• Conception Calculator by Last Period

  Find your likely conception date and fertile days from your last period.

• Ovulation Calculator

  Predict ovulation days for your next three cycles.

• Fertile Window Calculator

  See the days you are most likely to get pregnant.

• IVF Due Date Calculator

  Calculate your due date from an embryo transfer date.

• Implantation Calculator

  Estimate when implantation may happen after ovulation.

• Pregnancy Test Date Calculator

  Find the earliest and the most reliable days to take a pregnancy test.

• Pregnancy Week Calculator

  See how many weeks pregnant you are today.

Ovulation Calculator

Ovulation and fertile days for a 21–35-day menstrual cycle.

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From the blog

• How Conception Works, Step by Step

  From ovulation to implantation: what actually happens when a pregnancy begins.

• How Due Dates Are Calculated (Naegele's Rule)

  Why due dates are counted from your last period, and how cycle length and ultrasound change the result.

• Signs of Ovulation: How to Tell When You're Ovulating

  Cervical mucus, LH tests, temperature and other signs that ovulation is near or has happened.

• The Fertile Window Explained

  Why there are only about six days each cycle when pregnancy is possible, and how to find yours.

• How Long Do Sperm and Eggs Survive?

  Sperm can survive up to five days; an egg about a day. Here's what that means for timing.

• Implantation: When It Happens and What It Feels Like

  Implantation usually happens 6 to 12 days after ovulation. Learn about timing, bleeding and testing.

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