An ovulation calculator (also known as a fertility days calculator) will help you determine your most fertile days by projecting the day on which you will ovulate.  You are most fertile right before and on this day.

Maria is so excited about trying to conceive that she is looking online to see what things might help.  She is delighted to find an online ovulation calculator. It is fun, and makes her fertility more real and easy to understand.  She is thankful that she has been marking her menstrual cycles on the calendar so she has the information she needs. She just enters a few numbers and like magic she knows what days she is most likely to conceive.

what is an Ovulation Calculator?

What is an Ovulation Calculator?

  • A tool to help you determine when you may ovulate
  • Helps you to predict your most fertile days
  • Helps you get pregnant
  • Most accurate for women with very regular menstrual cycles

Track ovulation using an ovulation calculator.  The calculator predicts the day you are most likely to ovulate, which is the day the egg is released from the ovary and is ready to be fertilized.

The calculator helps you predict your most fertile days.  The most fertile days are right before and during ovulation.

Get pregnant more quickly.  If you do not know when to try, you may miss these fertile days altogether in a cycle, and have to wait for the next month to try again.

Accuracy depends on your having a very regular menstrual cycle.  This means that your cycle is always the same length (for example, every 28 days).  This is because ovulation usually occurs 14 days before your next menstrual cycle, and this fact is used in the calculation of your most likely fertile days.

Since ovulation isn’t completely predictable, nor are the details of any given cycle, a calculator is really only giving an educated guessUsing other methods at the same time, like observing changes in cervical mucus or using a urine LH stick, can help you be more certain of your fertile days. 

Ovulation calculators are available online, so you don’t have to do any calculations yourself.  You need to know 2 things (3 for some ovulation calculators.  See the note on luteal phase below):

  • the length of your menstrual cycle
  • the date of the first day of your last menstrual period

Some calculators ask for your average luteal phase.  This is the number of days from ovulation to the end of your menstrual cycle (when you begin bleeding again).  If you do not know yours, use the average of 14 days for most women.  If you have been charting the signs of your fertility for a few months you can count the days of your luteal phase and use the average for you.

Read the article: “How Do I Figure My Luteal Phase For An Ovulation Calculator?”

You can also do the calculations to determine your most fertile days yourself.  Online ovulation calculators are convenient, but it is good to know what lies behind the automated calculation.  It is the length of your average menstrual cycle (for example 29 days) minus the number of days between ovulation and the start of your next period (for example 14 days).

The ovulation calculator will tell you that you are most likely to ovulate on cycle day 15.  If your last period started on the first of the month, that means you may ovulate on the 15th.  You are typically fertile for up to 5 days before ovulation and the day of ovulation.  Make love during these days to improve your chances of conception.

To Your Vibrant Health!

Veronica Tilden, DO