OPK Ovulation Predictor Calculator

Fertility Tools

Obie Editorial Team

How does the ovulation predictor calculator work?

Ovulation is one of the most important things to learn about when trying to get pregnant. You need to ovulate in order to become pregnant. But how do you know when you are ovulating? The (OPK) Ovulation Predictor Calculator calculates the time when you should start testing for the LH surge. This calculator can also identify your expected date of ovulation based on the first day of your last period and your cycle length.

How do you test for luteinizing hormone surge?

There are currently over-the-counter urine tests called OPKs or ovulation predictor kits that measure the surge in urine. According to test manufacturers, the OPK test results are 99-percent accurate.

There are two forms of over-the-counter LH surge testing kits, commonly marketed as ovulation tests. The first measures LH in urine for seven days. Women need to calculate the correct seven days to use the kit based on the menstrual cycle and cervical mucus changes.

Many women choose to use the calendar method to track ovulation cycles. This will also help you choose the best time to perform LH surge home testing.

What is ovulation?

Ovulation is the time during your menstrual cycle when the egg is released. Taking a normal menstrual cycle into consideration, the woman will ovulate between the 10th and 19th day after the starting day of the last period. While the ovulation predictor may help to predict when ovulation will occur, you will need to have intercourse before ovulation in order to optimize your chances of conception.

Ovulation is like a marker. You can use the ovulation prediction kit to mark the day when ovulation will most likely occur, but two to three days before the day of ovulation is when intercourse should be planned. After the egg is released, it will only live in the body for up to 24 hours which is a small time frame for conception.

How do ovulation prediction kits predict ovulation?

Just like the at home pregnancy test is created to test for the pregnancy hormone hCG, the at home ovulation kit tests for LH. LH is the luteinizing hormone that rises in the body when the egg is about to be released. This continuous testing of the LH before the egg is released is needed to recognize a surge in the hormone. The ovulation prediction kit is created to test positive when a surge above normal range is detected. The hormone spikes BEFORE the egg is released, which is why the kit can make conception more likely. When the hormone spikes and the test result is positive, that day is the day to have intercourse.

Learning all you can about your fertility, menstrual cycles, and when (and if) you ovulate is the first step toward having a healthy pregnancy.