When Did I Conceive?

So, you're pregnant. But when did conception occur, and how can you determine the father?

While pinpointing the exact moment of conception isn't scientifically precise like tracking your period, understanding timed rhythms and cycles can provide a close estimate of when conception likely occurred.

What Date Did I Conceive?

There’s some simple math you can perform to confidently know around the time you conceived, whether you’re 2 or 20 weeks into your pregnancy. 

On average, there are two-to-three days when you ovulate (the time when your body can get pregnant) each menstrual cycle. This occurs about two weeks after your last period started.

Conception Date Calculator

By calculating the time since your last period, you can get a rough idea of your ovulation window and, hence, when you conceived.

If that math is a bit challenging to do in your head, there are free online calculators, or you can text us at (802) 736-7464 for help figuring it out.

Again, this is just a rough approximation. It’s important to remember that each woman’s menstrual cycle and ovulation window are different. Some ovulate for longer periods of time than others, and some have theirs earlier or later during their menstrual cycle.

Additionally, sometimes, sex before the ovulation window begins can still lead to pregnancy. That is because sperm can survive for up to five days, meaning pre-ovulation sperm can still fertilize an egg if it lasts long enough.

Conception Calculator

Conception Date from Ultrasound

Another way to determine the conception date is through an ultrasound. Fetuses typically grow at a steady pace, allowing for a precise measurement of their age. Therefore, an ultrasound can provide a more accurate estimate of fetal age compared to an ovulation calculator.

Having an ultrasound not only helps you know when you conceived but can also confirm the viability of the fetus.

You can have an ultrasound performed at your local OBGYN office; however, there’s usually paperwork and billing involved. Alternatively, your local pregnancy center may be able to offer free ultrasound services without the need for hospitals or insurance companies to get involved.

Get Help Determining Your Conception Date

If you need help figuring out which day you conceived or if you have any questions about pregnancy in general, we’re here to help.

Simply text (802) 736-7464 to speak with a real, registered nurse who will answer your questions and walk you through your options.