Do you want to get pregnant as quickly as possible or plan the timing of your pregnancy? Then it helps to know your cycle well and understand when you can actually conceive. Our ovulation calculator shows you when your fertile days are and when your chances of pregnancy are highest.

What is the purpose of the ovulation calculator?

When you’re trying to conceive, knowing the approximate day of ovulation can help increase your chances of pregnancy. However, every woman's cycle is unique, and calculating it on a calendar can quickly become confusing—especially if your cycle doesn’t match the “standard” 28 days. The LILLYDOO Ovulation Calculator makes it easier to determine your ovulation and fertile days and shows you when the probability of conceiving is highest.

This is how ovulation is calculated

Ovulation occurs about 14 days before the start of your next period and therefore depends on your cycle length. For example, if your cycle lasts 30 days, ovulation occurs approximately 16 days after the start of your period. However, cycle length varies from woman to woman and typically ranges between 25 and 32 days. Accordingly, ovulation occurs earlier with a shorter cycle and later with a longer cycle—roughly between days 11 and 18 after your period begins.

As long as you know the first day of your last period (the day bleeding begins in full force) and your average cycle length, our ovulation calculator will estimate the likely timing of your ovulation as well as your fertile window, the expected day of implantation, and the earliest date from which pregnancy could be detected via a blood or urine test.

Calculate your fertile days now

Symptoms and other methods for ovulation detection

Even if the ovulation calculator gives you a helpful overview of your fertile days, every cycle is individual, and ovulation can shift by one, two, or more days. If your cycle varies greatly, pinpointing ovulation can be difficult. With a stable cycle length, however, ovulation timing is usually more consistent. There are also additional methods you can use that—if you know your body well—may help you determine ovulation more accurately:

• Observing cervical mucus : It changes in consistency and color. On infertile days, it is usually thick, sticky, and white; around ovulation, it becomes thin, clear, and stretchy between your fingers. To get a sense of its consistency, run your finger over the vaginal opening and insert it until you reach the cervix. If it forms threads when you pull your thumb and forefinger apart, the cervical mucus is stretchy.

• Measuring basal temperature: This is your body temperature measured immediately after waking. Before ovulation, it is noticeably lower than it is afterward. Important: for reliable readings, you should wake up at the same time each day.

• Determination with an ovulation test: Test strips from the pharmacy measure the concentration of the hormone LH in your urine. This level increases significantly shortly before ovulation.

• Change of the cervix: With some practice, you can feel your cervix to determine which phase of your cycle you are in. As ovulation approaches, it becomes softer and sits higher in the vagina than it does after ovulation. During infertile days, the cervix is firm and closed.

• Observe physical symptoms: Some women notice ovulation through symptoms such as lower abdominal pain, tender breasts, or increased libido.

This increases your chances of getting pregnant

Unprotected sex on the day of ovulation doesn’t necessarily mean you will get pregnant. The probability that an egg will be fertilized is about 30 percent per cycle when both partners are fully fertile. To increase your chances, it’s best to have sex every two to three days during your fertile days—ideally four days before, two days before, and on the day of ovulation itself.

Good to know: You are fertile for this long

From your first period until menopause, usually one egg matures each month in your body—sometimes even several—and is released during ovulation and transported into the fallopian tube, where it can be fertilized. The egg’s lifespan is limited: it takes between 12 and 24 hours to travel through the fallopian tube, during which it can be fertilized; afterward, it dies. Healthy sperm cells, on the other hand, can survive for up to five days in the female body. This means you are not only fertile on the day of ovulation, but also up to five days beforehand and about 12 hours afterward. Per cycle, there are therefore roughly five days during which you can become pregnant.

It is still not possible to influence your child's gender with absolute certainty. Only medical options could provide one hundred percent certainty—however, gender manipulation of embryos is prohibited for ethical reasons.

With the ovulation calculator, you can determine your ovulation and fertile days, narrowing down the time when your chances of conceiving are highest. However, the calculations are based on a general pattern and can only provide approximate values: your cycle is individual and may fluctuate. Therefore, the calculator is not suitable as a contraceptive . If you do not want to become pregnant, be sure to consult your doctor about suitable contraceptive methods. If you want to become pregnant and your cycle has been very irregular for several months, your doctor can help you as well. The most important thing when planning a pregnancy, however, is this: don’t stress yourself, and try not to put too much pressure on yourself with probabilities and calculations while trying to conceive.