The other day, I posted a way to manually calculate your conception date if you know when your last period started as well as have regular 28 day cycles. there are other ways to predict ovulation date by many methods including cervical mucus and temperature charting as well as purchasing fertility testing kits.
Knowing your due date as well as your conception date is important. It might be especially important for you to find out what day you got pregnant from a paternity perspective. While the calculators can be very helpful, you do need to have a good grasp of when you had your period and if you’re not regular, you might need help from an ultrasound to do measurements and estimate the date of conception. Babies can grow at different rates so an EDD (estimated due date) could change throughout your pregnancy.
Here is a list of a few online pregnancy calculators to help you determine the date you probably conceived which include backward or reverse pregnancy calculators to give you the estimated date of conception based on a due date given by a doctor or ultrasound technician.
http://www.mymonthlycycles.com/home.jsp
http://www.mybirthcare.com/calculator.asp
http://www.mayoclinic.com/health/due-date-calculator/PR00099
The best way to ensure accuracy of family planning includes keeping a diary to help you track various items including dates you had sex, menstruation dates and perhaps information about cervical mucus and temperature. Calculators online can be very accurate if you have plenty of information.
Tags: conception date, edd, pregnancy calculator
February 12th, 2009 at 10:33 am
I was declared 15 weeks pegnant on the 18 jan 2008. had sex with a partner on the 16-17 october 2008 and another partner on the 23 and 28 october 2008. my last period was on the 7 october 2008 and i am on a regular 28 day cycle. what could be the possible conception date.
February 12th, 2009 at 3:13 pm
Hi Worried,
Unfortunately, the window of fertility for your #’s is estimated from 10/17 to 10/22 so there’s no real way to tell for certain without paternity testing. The 10/17 date is more likely but the 23rd is still possible.
Best wishes…
December 19th, 2009 at 12:58 am
I had sex on november the 24 with thhis guy in between my boyfriend I took a test like a week and a couple of days after that negative me and bf countined to have sex decenber the ninth tenth or eleventh I missed my period to a test on the fifltteenth came up positive my cycle cums the same day everymonth wat is thr possibility of that fling to have gotten me pregnant
March 1st, 2010 at 6:26 pm
I didnt have a period in July when i went to the doctor august 27th she said i was 6 weeks and 4 days. my estimated due date is April 15th. When did i conceive?
March 1st, 2010 at 6:30 pm
@anonymous, I’d count back approximately four and 1/2 weeks from August 27. If you were 6 weeks pregnant, the ovulation occurred about 2 weeks in to that cycle. You may need an ultrasound to be sure of the dates. Good luck.
July 2nd, 2010 at 8:07 pm
hi im really nervous. I am 28 weeks and 1 day pregnant. While concieving i had a fling. I had intercourse with the other man december 28. But i had sex with my bf on the 24 and 31 of december both times he ejaculated in me. i have done some of the calcualtors but im nervous because i need to kno who the father is.
July 2nd, 2010 at 8:08 pm
my lmp i think was dec.17 and my due date is september 23
July 2nd, 2010 at 8:13 pm
I’d say that if you had a lmp of dec 17 and you have a 28 day cycle that chances are that you wouldn’t have ovulated until after the 31st but it’s hard to say with the 28th & 31st being so close…Good luck. I’d look into a paternity test.
July 30th, 2010 at 1:40 am
Hi I had sex on the 9.01.2010 an I had a light period on the 11.01.2010 - around the 14th n 15 .01 .2010 , I then had sex on the 23rd n the 26th .01.2010 n found out I was pregnant on the 8th february , which out of them dates is when I was most likely to concieve ?
July 30th, 2010 at 1:56 am
Anon:
Really difficult to say without knowing your last period. If you know the first day of your last period, count 14-16 days from that day and that’s when most women (who have predictable 28ish day cycles) would be fertile.
August 25th, 2010 at 1:51 am
Hi! im just worried, I had sex with my partner on April 13, 15, 21 and May 7. Then had sex with another partner on April 27 at around 1:OO A.M., When could be the possible date that I had sex that I got pregnant??My due date accdg to the ultrasound said that it will be on Feb 5, 2011. While another doctor said it’s on Jan. 25, 2011… Please help.. I’m really confused…
August 25th, 2010 at 1:55 am
Just an additional info, I had my period during April 18-23…Please help me….
August 25th, 2010 at 1:56 am
Kris,
As I mentioned directly above your comment, if you can go by your last period, it’s the most accurate way to determine it — if your cycle is regular. I checked a due date calculator for conception date by due date and it said: January 25 due date would be a conception date of between April 27-May 4.
February 5 due date suggests conception occurred between May 8 and May 15.
Because of this contradiction in due dates, you’re probably going to need a paternity test.
Good luck.
August 25th, 2010 at 2:00 am
Kris, based on your LMP, if it’s a typical 28 day cycle, you ‘most likely’ (although not guaranteed) May 2. Unless you have a short cycle of 25 days or less, it’s doubtful that you conceived on April 27.
I’m not an expert! I’m just using online calculators and what I know about fertility from my own experience / research.
A DNA test wouldn’t hurt!
August 30th, 2010 at 2:33 pm
had sex on day nine then again had it on day 16 and my cycle is for 29 days when did I realy concieve thanks anonymous
August 30th, 2010 at 3:20 pm
Most likely on Day 16, anonymous…
August 30th, 2010 at 3:21 pm
PS: IF you’re counting from day one (the first day of your last period). Some make the mistake of counting from when they’ve finished their last period and that’s not the right calculation.
September 3rd, 2010 at 12:19 am
I had my last period on April 3rd-7th. Had sex with a guy April 9th then went and visited my ex(who is now my current bf) on April 10th and again on the 17th. I remember him saying oops and it was unprotected,but he told me it was nothing. Missed my next period but wasn’t fully aware that I was pregnant until I took a test on May 13th. Everything I’ve looked at shows that I concieved the 17th or shortly after. Does that mean It’s my boyfriends or is there still a chance it’s the other guys?
September 3rd, 2010 at 1:06 am
If your periods are regular and avg 28 days apart I’d say your conception date is most likely the 17th. I’m not an expert but that’s my guess…
September 3rd, 2010 at 3:09 am
Thanks for the help Dana Prince…