Ovulation Calculator

Use the ovulation calculator to see which days you are most likely to be fertile

Ovulation Calculator
When did your last period start?
E.g. 18/01/2020
Usually, how long is your cycle?
Cycles typically vary from 23 to 35 days
Estimate your ovulation day
likelihood of ovulating today
Due to your cycle length, unfortunately we can't estimate an ovulation probability. We recommend that you use a Digital Ovulation Test to accurately detect your most fertile days.
Start of your last period
Likelihood of ovulating on this date
Change my informations
In partnership with Clearblue®.
Results are based on the information you have provided and data from the publication below: Sarah Johnson, Lorrae Marriott & Michael Zinaman (2018): “Can apps and calendar methods predict ovulation with accuracy?”, Current Medical Research and Opinion, DOI:10.1080/03007995.2018.1475348

Ovulation calculator

If you’re trying to get pregnant, ovulation is key. Knowing when you are most likely to ovulate can help you plan sex accordingly and increase your chances of conceiving.

Our ovulation calculator is a simple tool that can give you a better understanding of your menstrual cycle and help you pinpoint your fertile window. Just enter some basic information about your cycle and our calculator will do the rest, estimating which days you are most likely to ovulate.

ovulation calculator

This ovulation calculator provides an estimate of your fertile window and is not a guarantee of pregnancy or of birth control. The calculator and information on this website are not medical advice. Talk to your doctor or nurse to plan for pregnancy and find birth control that works for you.

Fertile windows are different for every woman and can be different from month to month in the same woman. Learn more about your fertility if you are trying to get pregnant.


What is Ovulation?

Ovulation is the release of an egg from one of the ovaries. It usually happens about midway through the menstrual cycle.

The egg then travels down the fallopian tube to the uterus, where it may be fertilized by sperm. If fertilization doesn’t occur, ovulation is followed by menstruation.

ovulation can be affected by many factors, including age, stress, diet, and exercise. Often, ovulation occurs without any symptoms.

However, some women may experience bloating, breast tenderness, or light spotting around the time of ovulation. 

Ovulation typically happens about 14 days before the start of a woman’s next period.

For example, if a woman has a 28-day menstrual cycle, she will ovulate around day 14.

However, cycles can vary in length from 21 to 35 days, so ovulation may happen earlier or later in the cycle.

Tracking ovulation can help couples who are trying to conceive because it can help them identify when they should have intercourse.

It can also help women who want to avoid pregnancy to determine when they need to use contraception. There are several ways to track ovulation,

How do I calculate my ovulation?

Ovulation. The process is often called the ovulation calculator. Many women have cycles that are longer or shorter than the average 28 days.

The ovulation period is usually between 12 and 16 days before your next period begins.

If your cycle is shorter or longer than 28 days, you can calculate ovulation by subtracting 14 days from the length of your cycle.

For example, if your cycle is 30 days long, you would ovulate around day 16.

You can also use the above online ovulation calculator to estimate when you ovulate.

Simply enter the first day of your last period and the average length of your cycle, and the calculator will do the rest.

How accurate is this ovulation calculator?

An ovulation calculator is a tool that can be used to estimate the date of ovulation.

There are a variety of factors that can affect ovulation, including the length of the menstrual cycle, the timing of ovulation relative to the menstrual cycle, and individual variation in hormone levels.

As a result, ovulation calculators can be quite accurate in predicting ovulation for some women but less accurate for others.

If you are trying to conceive, it is important to track your ovulation cycles carefully so that you can time intercourse accordingly.

Your doctor can also help you to determine the best time to conceive based on your individual cycles.

What is a fertile window?

The fertile window is the days in a woman’s cycle when pregnancy is most likely to occur.

The fertile period begins on the day that ovulation starts and ends on the day before the next period begins.

During this time, an egg is released from the ovary and travels down the fallopian tube. If sperm are present in the Fallopian tube at this time, fertilization can occur.

The fertile window typically lasts for 6 days, with ovulation occurring on the 6th day.

However, some women have a shorter or longer fertile period, depending on their individual cycle.

To increase the chances of becoming pregnant, it is important to have sex during the fertile window.

What is a menstrual cycle?

The menstrual cycle is the natural process that a woman’s body goes through to prepare for pregnancy.

It typically lasts around 28 days, but it can vary from 21 to 35 days.

Each month, an egg is released from one of the ovaries and travels through the fallopian tubes to the uterus.

If the egg isn’t fertilized by a sperm during that journey, it will dissolve and be shed along with the lining of the uterus during menstruation.

If fertilization does occur, the egg will implant itself in the uterine lining and continue to develop into a fetus.

How to detect ovulation


High Libido

ovulation spotting

Ovulation spotting may occur


High temperature


Nausea and Headache


Position change in cervix

These are some early signs of ovulation. Keep a check on them

If you’re trying to conceive, keeping track of your ovulation is key.

Luckily, there are lots of ways to do this – from period-tracker apps on your smartphone to old-fashioned charts and diaries.

The most important thing is to be consistent with your tracking so you have an accurate picture of when you ovulate. 

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