How to use the calculator?

Information we need

Last Periods start date or LMP “The first day of the latest menstrual period. Cycle Length – It is an average gap, in days, between the first day of 2 consecutive periods. You need to measure the duration of the cycle for a couple of months by noting down the first day of the period and the first day of next period to get a fair idea on the menstrual cycle length or Average cycle length.

Information you get

Fertile Window: There is only a few day’s window (fertile window) when you can get pregnant. The window is typical of 6 days accounting to the average age of the sperm (6 days) and the age of egg (available for fertilization) which is 12-24hr. Knowing this window is crucial if you are planning to have a baby. Any sex outside this fertile window will have very low to no chance of pregnancy. Most Fertile Days: The fertile window of 6 days gives you a fair chance of getting pregnant. Within this fertile window, the most fertile days are the day before ovulation and the day of ovulation where the chances of getting pregnant are the highest in the entire menstrual cycle. These 2 days are of peak fertility and are called as the most fertile days. Period Start date: The tentative start day of your periods based on the information on the first day of the previous period and your average cycle. Pregnancy Test Date: The date when you can take your pregnancy test if you have missed your periods.

How does the calculator work?

The calculator works by identifying the ovulation day based on the LMP (Last Menstrual Period) date and the average menstrual cycle length. The ovulation is the release of an egg from a matured follicle into the fallopian tube. The egg travels towards the uterus and spends 12-24hr in the fallopian tube. This is the only time when the egg can be fertilised. So, if sperm is available at the time of ovulation you can get pregnant. The average length of the menstrual cycle is 28 days which makes ovulation day on 14th day but the length of the menstrual cycle varies from women to women and cycle to cycle but is usually 23-36 days. Irrespective of the cycle duration the ovulation happens 12-16 days before the first day of next period. Considering the average, the 15th day before the first day of the next period becomes the ovulation day. The sperm can live up to 5 days in the women body and egg can be fertilized for 12-24 hr after ovulation. So, the fertile window is of 6 days i.e. 5 days leading to ovulation day and the ovulation day and the most fertile days are the ovulation day and a day before that. The period start date is calculated by adding your average cycle length to the last period date. Ideally, if you missed your periods, you can take a pregnancy test the next day. Are there other methods to identify fertile days? Yes, there are a couple of other methods based on parameters like Basal temperature, hormonal changes, saliva changes, cervical mucus changes, etc.

What to do if u missed periods and the pregnancy test is negative?

You should ideally wait for 1 week before taking the test again. If you get periods within this week, then calculate your average cycle again and check for next fertile days from the fertility calculator. If no periods, take the test again after one week as sometimes the hCG levels are below the detection limit for your home test.