Conception Due Date Calculator

Conception calculator: work out your best fertile days

Working out the very best days to conceive can be tricky and having a calculator to do the work for you can remove the guesswork usually involved. By understanding the relationship between the dates of your last period, the length of your cycle and ovulation dates, you can more accurately plan conception and hopefully have your longed for child. Let’s begin by exploring what the calculator is used for and then progress on how you can actually use it.
Calculate your fertile days easily
By working out the best days to try to conceive you can improve the number of months it can take to become pregnant – something that can help with planning a family or when your busy lifestyle means you may have lost track of your periods or counting the days. For each woman, the conception days will vary and relies heavily on the natural body cycles – although it is worth noting that these cycles can change with stress and outside factors. Even the stress of trying to become pregnant can change the natural cycle of the body.
Using the conception window calculator
In order to use the conception calculator to its best effect, it is important to keep some dates in mind. These include the first day of your last period and the average length of your cycle. By keeping track of this for a few months you can have a good idea when the time comes to try and get pregnant. However, most women can assume that their cycle will be around 28 days as this is the average.
When added to the conception calculator, these dates will give you the best days for conception within a 2-3 day ovulation window. If you are already pregnant, you can use the calculator to work out the date of conception based on the due date, which can be roughly estimated by an ultrasound.
Please see below for a more detailed explanation of the best way to use this calculator
How accurate is the conception window calculator?
If you know your dates well and have been tracking your cycle, you can rely on the dates fairly accurately – but as already mentioned, your cycle can vary enormously and therefore be affected by stress, activity and your diet.
How to use the conception calculator
It is straightforward to use the Conception Calculator, provided you have already kept track of your periods and can say with certainty the first day of your last period.
You simply add this date to the first line of the calculator, using the calendar function to make this even easier. This first date should be when your period began fully as some women experience spotting in the days leading up to their periods. Thus, you should not count these days.
On the second line of the calculator you should add the average length of your cycle. For most women this is 28 days, but you may find it worthwhile to track your cycle for a few months to find out what your average is. Anything from 25 to 31 days is perfectly normal.
Therefore, if you arent sure, then you can simply enter 28 days as a rougth estimate. However, be aware that there may be a few discrepancies due to the changeable nature of your periods.
Conception day
Once you have added these details you will be given a number of columns that detail various information you might need. The first is the Most Probable Conception Day. This is the day you are most likely to become pregnant and is given as a range of dates for the next few months. These days usually cover 4 days when you are at your most fertile and most likely to become pregnant.
best intercourse days
The second column gives a list of days when you should have intercourse for the best chance of becoming pregnant. These best intercourse days do coincide with the fertility days, however they take into account the fact that sperm can live inside a woman’s body for up to 2 days, therefore you can have intercourse before you are fully fertile and still become pregnant.
possible conception day
The possible conception days column offers further insight into the chance of becoming pregnant during the month. This is a broad range of days that can be up to 10 days long when conception is possible. This may be a lesser chance than on the other dates mentioned, but there is still a chance, making it wise to consider intercourse on these days
Due date
Finally, the estimated due date gives the day when your child is likely to be born if you conceive on the dates given above. Due dates are always worked out based on the first day of the last period. However, these dates are subject to change and can be pinpointed with more accuracy during a scan. Few women give birth exactly on their due date, with many going overdue. This could be down to a lack of certainty over the date of the period or simply the fact that all women have different bodies.
How accurate is ultrasound dating?
Ultrasound conception dating is based on the size of the fetus and will be worked out based on the average for your approximate number of weeks. It is less accurate therefore than knowing the date of your last period. Our calculator will always give a more accurate date if you know your body’s cycle.
By using this calculator in reverse, you can choose the approximate day that your child will be born and then decide when it is best to have intercourse for that to happen.
Using the conception calculator to avoid pregnancy
It is possible to time your intercourse days to avoid pregnancy, by having sex outside of the ovulation dates. This is a risky form of contraception, as already explained, sperm can live inside a woman for a couple of days, making it possible to become pregnant when you do not expect to. However, with proper discipline and other methods such as watching the body temperature, it may be feasible to have a higher chance of not becoming pregnant.
Don’t forget that any ovulation calculator is only as good as the information given. Additionally, any changes to your lifestyle may seriously affect your chances of becoming pregnant.
A variety of factors can alter your cycle; these can include stress, diet and nutrition. So, taking care of yourself and your partner is essential.