You want to know the dates of your next period, ovulation or due date? You came to the right place. If you’re in a hurry you can go straight to our menstrual cycle calculator (click here) or Infographic with key information about calculating your period (click here).
Check the full table of content below.
Table of Contents
- Introduction
- Period & Ovulation Calculator
- How Do Menstrual Cycle Calculators Work?
- Using a Period Calculator
- How To Calculate Your Next Period & Ovulation Infographic
- Understanding the Menstrual Cycle Properly
- Understanding Your Next Menstrual Cycle and Fertilization.
- Some Important Information Regarding the Calculator
- Learn more
- Frequently Asked Questions
Introduction
If you want to stand the best chance of getting pregnant, then you need to know when you are ovulating. This is the time of the month when women are in their most fertile period. Ovulation usually happens around day 14 of the cycle [1]), while there is a greater chance of a sperm reaching the egg and fertilizing it.
However, one of the biggest problems and question that people have is knowing how to calculate their next ovulation date and when is the best time to aim for intercourse. This is where technology can come in handy. You can use an ovulation calculator, like the one below, to get a rough estimate of when you are going to ovulate next.
Ovulation & Period Calculator
Use this period calculator to calculate your next period (menstruation), fertile period, ovulation, and due date. To give you an estimate as to when those time frames are, please provide the requested information and press the Calculate button (results will be shown below, together with a fertility calendar):
When did your last period start?
How many days did it last?
How long is your cycle?
Below are the results based on the information you provided:
Your next menstrual period is expected to start on
Your next most fertile period is from to
If you conceive within this timeframe, your estimated due date will be
- Pre-Period
- Period Days
- Post-Period
- Peak Ovulation
Please note that this is only an estimation of your menstrual cycle
A period calculator is not the same as talking to a healthcare professional, so this is just to aid you in coming up with the most accurate calculation possible, on your own.
Also, keep in mind that these calculators will be useful to women with a fairly regular menstrual cycle. For women with irregular menstrual cycle tracking other ovulation symptoms or using an ovulation predictor kit might give more accurate results, all of which we’ll cover later one.
How Do Menstrual Cycle Calculators Work?
Menstrual Cycle Calculators vary in complexity. Some will ask you for information such as your average body temperature, as well as various other bits and pieces about what your body is currently going through.
While there are women who measure their basal body temperature, it’s not something that the everyday woman uses.
However, it is a rather accurate way (when done 100% correctly) to determine when a woman is ovulating.
Some feel that these types of cycle calculators are “overkill”, but for those who are using the basal body temperature to prevent and plan a pregnancy, they have this information handy.
If you aren’t into this type of strict monitoring, a simple calculator like the one provided here can give you really good results and help you plan.
Using a Period Calculator
The first thing that the period calculator will ask you is the date of your last period. With so many apps available now, this should be information that is readily available.
And just remember, when calculating your period, you use the first day of your last period. This was the beginning of your cycle.
If you don’t know the exact first day, calculate back from the last day however long it lasted, and start tracking now. Especially if you are trying to get pregnant.
Some will use a menstruation calculator to figure out when to expect their periods and when to expect PMS. PMS is due to the change in hormones that cause periods and pregnancy.
When you are pregnant or during your period, these emotional and physical symptoms subside [2]. Some women can then plan to change their diet a few days before they expect PMS and help to alleviate some of the symptoms.
The next piece of information that you will be asked for is the average length of time between your periods. This is the length of the menstrual cycle. Of course, the human body does vary wildly here, and whilst some months there could be 30 days between your period, others it could be as low as 25.
However, you are only after an average here. Being as accurate as possible is important as this will affect the results that you are given which can have a profound effect on when the calculator tells you is the ideal time to try for a child.
Finally, you will be given your results. Based on the information you provided, it will calculate when your next period is anticipated and also your fertile period which is when you stand the best chance to get pregnant.
How To Calculate Your Next Period & Ovulation Infographic
Understanding the Menstrual Cycle Properly
While you may already have a fair understanding of your own menstrual cycle, there are women who have cycle lengths that vary. Sometimes, your own cycle can be as short as 23 days on cycle and 28 or 30 days the next.
When a variation in menstrual cycle length occurs, it usually happens before you ovulate. This is referred to as the follicular phase which encompasses menstruation as well and ends when you ovulate [3]. A woman generally ovulates between days 12-16 of their cycle which is the start of the luteal phase [4].
There is a multitude of reasons as to why your period could be altered, be it stress or medications, even weight gain/loss or travel. Unless you think you are pregnant, it could be a myriad of reasons that have your period coming irregularly.
Understanding Your Next Menstrual Cycle and Fertilization
If you are trying to get pregnant you need to understand how the menstrual cycle works. The process starts when the thick lining of your womb starts to break up due to the decrease in estrogen and progesterone levels.
Without a sufficient amount of these hormones, your body will shed the lining and it will start to prepare for your next menstrual cycle.
However, if a sperm does make contact with and fertilizes the egg, it will close all pores to prevent more sperms from getting in there. The fertilized egg will stay in the fallopian tube for 3-4 days and then move to the uterus and attach to its wall, staying there for the long haul of pregnancy.
Your body will produce human Chorionic Gonadotrophin (hCG) or pregnancy hormone right away (which can be seen within 6-8 days by a blood test and can take about 2 weeks if not longer to be seen in urine tests) [5].
The body will continue to produce the required estrogen and progesterone hormones so that the womb lining will not be shed and the placenta can grow mature enough that it can support the pregnancy.
Some Important Information Regarding the Calculator
The period calculator above also comes with a fertility calendar. You can navigate through different months by clicking on the NEXT 2 MONTHS and PREVIOUS 2 MONTHS links. This allows you to plan and prepare for your fertile and menstrual periods in the upcoming months.
What you do need to remember though is that the information isn’t 100% accurate as it is impossible to predict the human body.
Your fertile period gives you a good range in when to have intercourse to potentially get pregnant. You can learn more about the likelihood of conception in this article.
That being said, the menstrual calculator is still an extremely useful tool. It provides a simple way of knowing when to anticipate your next period and when is the best time to try for getting pregnant.
This could be a huge help for those with busy schedules to plan their days to start their family.
Learn more
Want to learn more about your menstrual cycle? Find out how does the Fertility Calculator work or how to to calculate your period manually.
Want to know if you’re pregnant? Take this online pregnancy test, read more about the most common reasons why your period might be late or find out when it’s the best time to take a home pregnancy test.
FAQs
How do I calculate the length of my cycle?
Can I have sex during my period?
What is the average length for periods?
My period is really heavy; what can I do to change that?
Can I get pregnant if my periods are irregular?
How do I know if I need to see a doctor because my heavy periods?
Can I prevent PMS?
Do you have any other question about your period, ovulation, pregnancy or other related topics? Check out our Frequently Asked Questions page.
References
- Your Fertility. Women’s Guide to Getting the Timing Right [link]
- Mayo Clinic. Premenstrual Syndrome (PMS). [link]
- Better Health Channel. Menstrual Cycle. [link]
- see above #3
- WebMD. Pregnancy and Conception. [link]
- Eleanor Jones via Cosmopolitan. 10 Questions Period All Guys Want Answered [link]
- Playtex. Period 101. [link]
- The University of Iowa. Birth Control Pill Fact Sheet. [link]
- WebMD. Slideshow: Answers to Your Top period Questions. [link]
- see above #9





Hi I’m concern I’m not sure exactly what day my period came on during I do know it was between 16-18th of Aug and now I am wondering if I am pregnant or not because I haven’t seen my period yet this month of September??
My monthly menses is only 4 days, the first day of the month. LMP: 9/1 & I had engaged 9/12 & 9/14, what are the odds, what are my fertile days, & possible conception date?
Hi NY,Your next most fertile period is September 13, 2015 to September 17, 2015. It will be hard to tell exactly when you concieve, if you do the doctors will just count from the day you had your last period.
my first day period is on 25/08/15 finish period date is on 29/08/15 ,we have sex on 4th,6th,8th and 13 august ,when will be my period date or i have to check for pregnancy?
Hello Chris, You should check for pregnancy because it is always possible to become pregnant if you had unprotected sex
I had my period for 2 days on September 2 and it was supper light my boobs have been hurting and constant heart burn and sick to my stomach all the time. Did a pregnancy test and came back negative. Do you think it’d to early to tell could I be pregnant?
Hi Amy, you can still be pregnant with a negative pregnancy test. I suggest you take one more if its still negative visit your doctor.
Hi
I had my period yesterday that’s 18 September 2015.
when will it be my fertile days to get pregnant? Thanks
Hi. you didn’t tell us what’s the usual length of your cycle. if it’s 28 days then you ovulation will be from September 30, 2015 to October 04, 2015. use the calculator at the top of the page next time and check out our FAQ page:
http://womanjunction.com/faq-frequently-asked-questions-menstrual-cycle-pregnancy-ovulation-abortion/
Had my period August 17-22
It was a little short..
Took a pregnancy test about a week and half after that period ..it was negative.. now here it is 9/18/15 my normal day to start my period. . No period.. took a test it was positive.. can anyone tell me how many weeks I could be .. and more or less a time frame for when we might have conceived .. I’m asking because I’m worried about something in the time frame.. ????
Good morning everyone!!
Well my last cycle that i know was normal was August 9th- the 12th r 13th!! Yes i has sex with my boyfriend two to three times a week!! Well i was suppose to get my period. September 6th-9th r 10th but all i did was spot on the 6th-8th and it was very very light!! I took two home pregnancy test but both was negative!! Could i be pregnant or could somthing else be worng!? Please help!!
Hi Nicole, its always possible to be pregnant when having unprotected sex also you can still be pregnant even with a negative test I suggest you go to your doctor to make sure.
It is very likely that you are pregnant but your hormone levels are to low to register… I suggest that you wait for a couple of weeks and test again or go to the doctor and get a blood pregnancy test or get a ultrasound that will definitely tell you if you are pregnant or not.
my period was started today.which are most fertile days to me
Hi hafsa, please use the calculator on the top of this page. I would also suggest that you read our FAQ page:
http://womanjunction.com/faq-frequently-asked-questions-menstrual-cycle-pregnancy-ovulation-abortion/
My pms started on 24 August, my cycle is normally 30 days, me and my husband had unprotected sex on 3rd September and on 7th September, I have not been getting any signs as of now. Could i be pregnant , and when should I take a home pregnancy test.
Hi Kelly, please read our FAQ page:
http://womanjunction.com/faq-frequently-asked-questions-menstrual-cycle-pregnancy-ovulation-abortion/
Good luck!
Hi, my lmp was on sept 9 and lasted until sept 12 when would be my most fertile time. me & my husband are trying to concieve
Hi Kimberly, Your next most fertile period is September 21, 2015 to September 25, 2015
My lmp was august 13 til the 17th. My next one was due on the 10th of sept. I am currently 5 days late. I am regular and never been 5 days late maybe two or three late but not 5. I took a hpt came back negative and i took during the dat and not in the am. My nipple started to have this burning sensation the other day. Whats the next step.
Hi Shoni, sometimes you can be pregnant even with a negative test so I suggest you take one in the morning when your wake or visit your doctor. The sensation in your nipples is normally a sign of pregnancy.
Hello,
My last lmp was on July 17th and I had unprotected sex almost every day. I tried home pregnancy tests and it always shows -ve. I tested almost 6 to 7 times after August 20th to till date, results always -ve. Is there anything I should do to get accurate results?
Thanks!
Hi As,try taking the test first pee in the morning if its still negative go to your doctor.
My last period was 8th August and today is 14th sept and I haven’t received my periods yet. I had unprotected sex on 4th and 6th. I had a change of weather in the last 3 weeks. I don’t have any pregnancy signs but haven’t taken the test. Could it be cause of the weather change that my periods are late or could I be pregnant?
yes, you could be pregnant, like every time when you have unprotected sex.
please use birth control if you don’t want to become pregnant
Hi, I saw my period on the 29th of august and I now saw it again today 14th of September, please is it normal. Thanks
Hi olalekan, you are not alone as many women complain about seeing their period even twice in one month I am not sure why this happens but if you are not experiencing pain its nothing to worry about if this happens just once.
My lmp was on 3/2/15 and I had sex on 3/14/15 3/20/15 and 3/23/15 which of these days would I have most likely conceived ?
Hi Katie, Your most fertile period would be March 14, 2015 to March 18, 2015.
Hello, my last menstrual cycle was on August 13, and my boyfriend and i had an unprotected sex on Sept. 8, i am expecting my menstrual cycle last sept 10, but already 3 days delayed. Is it possible that i’m pregnant? Though i’m experiencing soreness on my breasts and such. Thanks!
Hi Mj, Yes it is always possible to become pregnant when having unprotected sex,i suggest you take a pregnancy test in the morning when you wake.