My Fertile Time - Free fertility calculator

One of the reasons infertility is on the rise is the fact that couples are often not able to have sex during their fertile days. Especially in cities, where both the husband and wife are working, often on different shifts; or because they have to travel frequently because of their job commitments, it's not possible for them to time baby making sex during their "fertile period".

To make a bad situation worse, many couples are completely clueless about their fertile time and how to calculate it. While most women know that the fertile time is related to their ovulation and that women with a 28 day cycle ovulate on Day 14, they often do not know how to apply this generic information to their own cycles !

For example, if they have a 33 day cycle, then what is their fertile time ? And how often should they have sex during this time ? Should they try to save up the sperm ? Does the position matter ? It's hard to ask busy doctors all these questions, which means that old wife's tales and myths and misconceptions are still very prevalent.

Sadly, many doctors are also poorly informed. I remember a 28 year old woman who came to me. She had a regular 25 day cycle and her gynecologist had advised to have sex exactly on Day 14 to maximise her chances of having a baby. She had been juggling her work schedule and forcing her husband to have sex on Day 14 by the calendar religiously for the last 6 months, but had not got pregnant, which is why she came to me for IVF treatment.

I explained to her that by following her doctor's advise, she was actually making herself infertile ! Women with a 25 days cycle ovulate on Day 11 - which means they are infertile by Day 12 !
The formula is simple.
It is Date of ovulation = NMP - minus 14 days, where NMP is the estimated date of the next menstrual period ( which is fairly easy to guess if you have regular cycles).
Your fertile time for baby making sex is this day - and the 4 days preceding this. Once you ovulate, you actually become infertile !

You can also use our Free Fertility Calculator at

She was angry and upset when she realised how much valuable time she had wasted. I explained to her that she did not need IVF; and advised her to continue trying in her own bedroom, after explaining to her what her fertile time was. She conceived promptly in the second month and still invites me to her daughter's birthday every year !

Authored by : Dr Aniruddha Malpani, MD and reviewed by Dr Anjali Malpani.