How can I tell when I’m ovulating?
 
First, purchase a calendar that you can use to record your symptoms and times of menstrual bleeding. 

Find the date when your next period is due to start and count back 12 to 16 days.  This will give you the range of when you most probably will ovulate. 

The average woman has a 28-day cycle and day 14 is the most common date of ovulation.  When physicians say “Day 3” or “Day 14” or “Day 24” it simply means you count your first day of bleeding as Day 1 and go from there.  It does not mean the third day of the month or the 14th day of the month or the 24th day of the month.  Physicians do not use the day of the month.  They use the day of the cycle itself. 
 
You will need to be attuned to your body and learn the signs that ovulation is coming. 

Cervical Mucus increases in volume and texture. 

As estrogen rises towards the middle of the cycle the cervical mucus becomes clear, thin, slippery, and stretchy.  The texture of raw egg whites enables you to stretch the filmy mucus between your fingers to 8 centimeters or more.  This mucus protects and feeds the sperm in its path through the cervix, to the uterus, and up the tube where it meets the egg.  Sperm can live for 3-5 days in suitable cervical mucus.  Birth control pills are largely successful because they make the cervical mucus thick and inhospitable to sperm.

Body temperature rises after ovulation by 0.5 to 1.6 degrees. 

You will not feel this temperature change but you can detect this rise using a thermometer and plotting it on a chart.  This is called a BBT chart, or Basal Body Temperature chart. 

This temperature is taken the first thing in the morning before any activity occurs. 

A thermometer and BBT chart are placed right beside the bed and the first activity of the day is put the thermometer in the mouth and records this temperature. 

The temperature spike is due to an increase in progesterone that occurs when an egg is released. 
 
Low abdominal pain occurs in 20% of women who ovulate. 

This pain can be a mild twinge of pain on one side of the lower abdomen to a very distinct sharp stabbing pain caused by the physical rupture of the cystic follicle containing the egg and the irritating fluid released. 

The pain can last several minutes to a few hours.  The condition is called Mittelschmerz. 
 
The window of fertility is two or three days before the BBT hits its high.  You may have an additional 24 hours of fertility after you notice the creep-up in temperature but it may also be too late. 

It can take one to two days after ovulation for progesterone to achieve levels that raise body temperature.  However, an egg survives only 24 hours and it may be too late to achieve pregnancy if sex occurs at the peak temperature. 

Experts recommend that temperature charting be done for several months to detect a pattern.  Then if pregnancy is desired sex is planned during the two to three days before the anticipated day the temperature normally rises.