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





i am 46 years old and for the 6 months my periods have been very irregular as for the date I start. But have always had my period each month. My boyfriend and I use just condoms. My last period was July 22nd start date, lasted 3 days. Now as of September 23rd I have not had a period. I do not use birth control, the condom has not broke during intercourse. Is there a chance I have just gone through mentapause or could be pregnant? I don’t feel the effects of either.
Hi , you are right to pin point the possibility that your menopause is kicking in ! but dear ! do a test to clear that out ! Either way positive or negative, have an appointment with your physician to have a look !
Hi, I’ve been really anxious and excited to know if there’s a possibility i may be pregnant and want a second opinion. My period started on September 1st, my boyfriend and I had sexual intercourse on September 11th and he ejaculated inside me 2 times. Then we had intercourse on the 17th of September and he ejaculated inside me 3 times that day. What are the chances of me being pregnant? I wrote yesterday but never got a response back and i am really hoping i get one soon with a second thought, Please and Thank you!
Cathy ur prenant b/c ur most fertile date was 13-17 of september so congratulation in the month of may 2015 ur a mother thank u
Hi ,
Me and my girlfriend of 18 years old was just fooling around with our clothes(without any condom
) and i just inserted my one finger just through the “back of her underwear”..i think i had a bit of precum in my hands and im not sure whether i hav touched her vagina or not. I just touched something through her back,then i felt wet and suddenly i pulled out my hands!
We dont have any sexual intercourse or something and i think after that i ejaculated unknowingly and found some sperm and wetness on my clothes(not in her)!
it happened on Aug-8 and now its over one month!At that afternoon itself she told that she is feeling very tired and she got upset..she also forgot her date of period and got tensed! but the period occured on 23rd of Aug! now its 12th Sept and now she found some blue marks on her thighs and little pain!(Meanwhile she had a great play time with her cousins this week)!
im really tensed now and dont know how to tell her about this!(she dont knw whether she is pregnant or not! and if i asked het to take a test..it will upset her fully and she will loss concentration on studies)
will she be pregnant ? plz help me…
as I understand she got her period on 23rd of Aug (few weeks after that incident). if that’s the case she’s not pregnant. if she’s still experience that pain that you mentioned then she should talk with her physician
I calculated my Last Period on here which was August 24-30, 2014. My most Fertile Days Were September 5-10, 2014. I Had Unprotected Sex on the 10th of September. I have been experience some Symptoms, I am waiting to take a Pregnancy Test. The Symptoms I’m getting is what Pregnant Women get. Could I Be Pregnant? I would love to read what you think.
Thank You.
GP
Hi, Don’t get too exited until you get a positive result in your hands ! sometimes waiting for symptoms to show up lead your body to create it, don’t listen too much to your body to avoid to be disappointed, but enjoy fully the good new when it will come !
Good luck !
GP were you pregnant
The first day of my period was the 1st of September. My boyfriend and I had sexual intercourse on the 11th of September and he ejaculated 2 times. Then we had sexual intercourse again on the 17th of September and he ejaculated 3 times. Can i be pregnant? We want a baby and we are eager to know the possibilities.
Hi, most of the women, depending of the length of their cycle will have their fertile window between 10 to 14 days after the beginning of the cycle which is, period day 1. Also let me help you with your project, the amount of sperms is not what will make you pregnant… second and third ejaculation is most of it only seminal fluid with no or little sperm inside, so useless for conception, the best way to succeed to conceive will be to have intercouse one day on two to maximise que quantity of mature spermatozoids that will any way live 3 days in the womb.
good luck !
Ok hello, I haven’t seen my period since the 29th of July. My period usually is irregular but it’s now Sept 17 and it hasnt come on as yet? could I be pregnant?
Hi , Yes being pregnant is possible, other rason can make you skipping a cycle such as stress, new diet or gym routine. By now a simple pee on a stick can give you a clear answer… If it come negative, please visit your physician that can give you more answers
Good luck
Hi. I had unprotected sex on the last day of my menstruation just last sept1. I calculated here that I’m fertile in sept 9. Could i be pregnant?
Hi , I already did ! became pregnant having unprotected sex late in my period, but it is uncommon, to get in this situation you need to have 2 ovulations in the same month. You can test yourself as of sept 14 for the unprotected sex you has on sept 1 st, test should be reliable.
Good luck
The site gave me the dates Sept 8-13 as my most fertile. If we did conceive, when would be the earliest date we could test positive?
Hi. you will get a positive result if you conceive 14 days after the fertilisation ! so track in these day the last day you had intimacy and it will be for sure covering the previous attempt. You will notice that this lap of time is close to the moment your next periods are due, if you have a regular cycle !
Good luck
Hi,
My last period was on the 11th of August & i still haven’t come on my period. I still keep getting cramp type feelings and lots of “bubbling feelings in my tummy – I put these done to been anxious, but could it be signs of early pregnancy? as i’m now 4 day overdue on my period.
Please help :/
Hi , Well ! I guess that if you worry at this point is that you always had a clock set cycle ! Anxiety is the first reason why the period cycle getting disrupt along with dieting and intense exercising. If you doubt being pregnant .. to reduce the stress going along the unknown, test yourself ! Skipping a cycle is not dramatic but if you skip a second one I strongly recommend you to set a visit with your physician to make sure everything is all right !
Good luck
Hi, the first day of my last period was August 11th. I had unprotected sex on Sept 7th(the only time I did have sex since my last period) but before then I already had signs of the next period (softened breast). Yet till today Sept 11th, my period has still not started, could I be pregnant?
Hi , for a single try .. I have doubts but nothing is impossible. As soon you have 14 days past that day you had unprotected sex you can test yourself, with morning urine, you will get a good result as it is the one containing the higest concentration of HCG, if you are pregnant
Good luck
Hi, my period hasn’t start since july,19 , 2014 it’s sept.10 and no period no sign of pregnancy had negative test on all pregnancy test I’ve done.what should I do?
Hi, what changed in your life more then your period ? gym, diet, job, stress … age … skipping a cycle is not abnormal, but if you feel uncomfortable to skip a second one, have a visit to your physician, he will have official answers for you !
Good luck !
Pls help I saw my mense on 8/8/2014 now is september 11 I’ve not seen it why
Hi , depending if you always had a regular cycle or not, it might not be a major issue. As I am often saying stress, diet or gym routine can lead your cycle to delay or change. If you have doubt that it can be due to a pregnancy, test yourself to clear your mind from all your uncertainty.
good luck !
Plz help I saw my menses on the 29/ 03/2016 and now is 29 04 2016 I’ve not seen it why
Hi I have a question and i need some feedback. Ok In july i started my Menstrual Cycle July 26 and 15 days later i was back on my Menstrual Cycle Aug 10. Now 31 days later I still havent had a period what can be goin on?
Hi , you have an irregular cycle, always been like this or it is new ? new gym routine? stress ? new diet ? all these reason can lead to see some changes in your cycle, age as well … if you get close to your menopause. If it still keep being erratic and feel uncomfortable about it, visit your physician for some answers !
Good luck
My last period was August 22nd-24th. It was unusually short. I usually stay on for 5-7 days and my boyfriend and I don’t use any protection at all. I have been experiencing nausea for the last 2 weeks. Is it possible I could be pregnant even though I haven’t missed my period yet?
period can vary in length. as you got it last month it seems you’re not pregnant.
however, you’re taking a great risk if you continue having unprotected sex
Hi,my last period was July 14,2014,I had play with my boyfriend and he ejaculated just rubbing his penis to the upper part of my vagina I am sure it never touched the opening of my vagina,it was August 8 to 12,my period doesn’t come yet.and we are now in sept.7,I am 50 years old.
Hi ,
I have big doubt that you might be pregnant, but we never know life is always finding its way, test yourself, if it come negative, I recommend you to have an appointment with your physician .. might be the first sign of your menopause.. as skipping cycle is what happening at the beginning.
Good luck
Hi I missed my cycle, it was supposed to come on August 23 and I still haven’t got it…….. any answers
hi, you can read about some of the possible reasons in this article