# How to Calculate Your Ovulation Date

When a couple is struggling to conceive, knowing when to expect ovulation greatly increases their odds of conception. For eons, women have use the same method of counting days to predict their most fertile days. Unfortunately, that method only works for women who have regular, predictable menstrual cycles. But for a woman with irregular periods or a woman who doesn’t have periods, trying to predict when that magical day will be is a guessing game.

## For Regular Menstrual Cycles

### Step 1

Count the days from the first day of your last period to the first day of the next one. The most common number of days in a menstrual cycle is 28.

### Step 2

Divide that number of days in half. So, for a 28-day cycle you’d get 14.

### Step 3

Subtract that number from the expected date of your next period. For example, if you expect your next period on February 28, subtract 14 days. Your ovulation date will be February 14.

## Measuring Basal Body Temperature

### Step 1

Prepare a chart to track your basal body temperature for a full menstrual cycle. Using a digital thermometer or a thermometer specifically designed to measure basal temperature, take your temperature every morning before you get out of bed. Mark it on the chart.

### Step 2

Examine the chart at the end of your cycle and take note of the days of your highest basal temperature. You are most fertile two to three days before the rise in temperature.

### Step 3

Count the number of days into your cycle these most fertile days occur. Expect those days to be your most fertile during your next cycle.

## Ovulation Predictor Kits

### Step 1

Know when to expect your most fertile days by using the calendar method or by tracking your basal temperature. On the days you think you might be ovulating, use the ovulation predictor kit to measure luteinizing hormone (LH). Elevated LH levels occur right before ovulation.

### Step 2

Wait to take the ovulation predictor kit out of the package until you’re ready to use it. Like a pregnancy test, it measures hormone levels in your urine. Follow the instructions enclosed with the kit for proper results.

### Step 3

When the kit detects an LH surge, you will be most fertile for the following 48 hours.

## Warnings

• Although an ovulation predictor kit can make a good estimate about possible ovulation, it can’t prove ovulation will actually occur.