Ovulation Calculator

Wondering when to conceive? Find out about the different phases of your ovulation cycle and predict your prime time with this easy tool.

Select first day of your last period *





Frequently Asked Questions about Ovulation Calculator


How to use Ovulation Calculator & Fertility Calendar?

Select the first day of your last menstrual period, by tapping a day in the in calendar. Tap on the arrows > and < to navigate to the next or previous month.
Then select the average length of your ovulation cycle.
Tap the blue 'CALCULATE' button to view the results.
To fully understand the results it is strongly recommended that you go through all the FAQs below.

How accurate are online Ovulation Calculator & Fertility Calendar apps?

Most of the online ovulation calculators and fertility apps are often wrong or misleading.
Here is a simple litmus test. For women with average cycle of 14 days, most apps recommend day 11 to 15 as fertile days of cycle. However according to "Standard Days Method" (SDM) which is a viable method of contraception having effectiveness of 95%, days 8 to 19 of a women’s menstrual cycle are fertile period for women who have cycle length between 26 to 32 days.
You can clearly see that out of total 12 potentially fertile days many couples could be missing critical opportunities for conception each month if they follow these misleading apps.
Now if you try this Ovulation Calculator with cycle length of 28 days, it will identify a fertile period of 10 days from day 9 to day 18 of the cycle. To be more accurate there are chances of conception on day 8 and 19 also, which we have intentionally excluded, because on these days the chances of conception are very low about less than 2%. This clearly indicates that our application is much more precise and accurate.

What is a menstrual cycle?

When periods (Menstruations) come regularly, this is called the menstrual cycle. Having regular menstrual cycles is a sign that important parts of your body are working normally. The menstrual cycle provides important body chemicals, called hormones, to keep you healthy. It also prepares your body for pregnancy each month. A cycle is counted from the first day of 1 period to the first day of the next period. The average menstrual cycle is 28 days long. Cycles can range anywhere from 21 to 35 days in adults and from 21 to 45 days in young teens.

What happens during the menstrual cycle?

In the first half of the cycle, levels of estrogen start to rise, and makes the lining of the uterus (womb) grow and thicken. At the same time an egg, or ovum, in one of the ovaries starts to mature. At about day 14 of an average 28-day cycle, the egg leaves the ovary. This is called ovulation.
After the egg has left the ovary, it travels through the fallopian tube to the uterus. Hormone levels rise and help prepare the uterine lining for pregnancy. A woman is most likely to get pregnant during the 3 days before or on the day of ovulation. Keep in mind, women with cycles that are shorter or longer than average may ovulate before or after day 14.
A woman becomes pregnant if the egg is fertilized by a man's sperm cell and attaches to the uterine wall. If the egg is not fertilized, it will break apart. Then, hormone levels drop, and the thickened lining of the uterus is shed during the menstrual period.

When does ovulation occur?

For most women ovulation is likely to happen around the middle of the cycle. However there is lot of variability in length of menstrual cycle among women, and with in cycles in same individual. Even in women with fairly regular cycles the day of ovulation can vary by +- 3 days.
This calculator uses the results from multiple studies and precisely calculates the chances of ovulation on each day of the cycle. It gives you range of days in which you are most likely to ovulate. The chances of ovulation are high in the middle of this range and low near start and end days of this range.

How this Ovulation Calculator & Fertility Calendar calculates the ovulation date?

This calculator estimates the day you are most likely to ovulate based on data from latest studies. The results are based on your average cycle length and on start date of your last menstrual period.
In 50% of cases you are likely to ovulate within two days before or after the calculated ovulation date.
It also indicates a start and end date for ovulation. In 95% of cycles you are likely to ovulate within these dates.

What are Fertile days?

These are the days during your cycle, on which having an unprotected sex may result in pregnancy.

What is the difference between Ovulation and Fertile days?

Ovulation is the process of an egg being released from an ovary and this happens 12-16 days before next period starts.
Fertile days are the days during a woman's menstrual cycle, when she has the ability to become pregnant if she has unprotected sex.

What is meant by Low, Medium and High Fertility?

On the start of your fertile days there are very low chances of pregnancy (about 2% to 4%), Its indicated as “Low Fertility” in the report.
Your chances of getting pregnant reach the maximum around the middle of fertile days, its shown as “You'll be Most Fertile on” date in the report.
After this date the chances of ovulation and getting pregnant starts to decline.

Should we have intercourse every day I am fertile?

Sperm that are stored within the testicles for too long accumulate damage to the DNA and are less fertile. With couples who have frequent (daily) intercourse, the man will have a lower sperm count per ejaculation but the sperm will be more fertile. If you are trying to conceive then try to have intercourse, (preferably in the morning) at least every other day during your entire fertile period.

Trying for a boy or a girl?

Several theories claim you can influence the gender of your baby by having sex at a certain time of the month. All such theories lack scientific evidence and there’s no guaranteed, natural way to choose the sex of your baby. Your odds are 50-50 unless you use a sperm-sorting technique, followed by artificial insemination.


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