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 had my last period dec 23 I haven’t had a period none this month and I had sex a couple of time in jan but can’t remember exactly but I tested positive in jan 20 with urine 3 times but negative blood couple days later I been cramping so I went back to the hospital and tested positive urine and blood but they did ultra sound and seen nothing and they calculate from my last period which I should be about 5weeks and days from today so what does that mean I’m scared and nervous I have no signs of spotting and this month almost over
Hi , did the hospital confirmed the pregnancy ? Did they test you twice with the blood screening to compare if the HCG hormones are leveling up or decreasing. I cannot believe they let you out without answers… at 5 Weeks they see the gestational sac, if there is no embryo inside, it is what we call an empty mole, meaning that there is pregnancy hormones but no developpement .. it is normally ending in a miscarriage, most of the women will never notice it as they will just have their regular periods on time and they will be a bit heavier then usual .. but with no other symptoms. If you have doubt about the condition of your actual pregnancy, you should definitely have an appointment with your gynecologist or to find one. You need answers …
Good luck
Hi my last period was dec 24th of last year… i don’t always get my period the same day.. so i don’t really know how long my cycle is.. i had sex every other day for the whole month. Took test still negative what do i do?? The 24th has pass already today the 28th.??
Hi,
I guess that I can indeed suppose that you are trying to conceive ? You are doing it right by having intercours every second day. But, nature is capricious and it is not a guarantee that it will trigger at the first month trying. Keep going, enjoy these intimate moment and dont stress out about conception performance … it is one of the most common failure reason.
Good luck
i had my periods last on the 21 December 2014 had not gotten it breast tender clear blue says positive went to the doctor yesterday he says he cant see it on the scan yet i guess it would be about 3 weeks is that to early to see a sac etc.i am really confused,going to have my hcg quantity tested today.
Hi ,
3 weeks it is very early even to know you are pregnant ! Some medication can also trigger false positive. HCG hormone level don’t lie,either it goes up, either it is not there , or it goes down … you will get a final answer !
Good luck
I had my period on the 7th of this month, forgot to take the morning after after having sex on the 14th. What are the odds that I may have gotten pregnant?
hi,
your question is unclear, if you are talking that you forgot to take a birst control pill, one miss have no effect on the protection of the pill, if you forgot to take an emergency birth control pill because you had a failure of a mechanical contraceptive method, this is a different story.
hi my period started january 17 2015. i was wondering if i had sex on the 26th if it was possible to get pregant my expected fertile window is from the 28th and on.
Hi. My last period was 31 of December 2014. My fertile windows is January 10-14, 2015. Had see with my hubby during that period. My next menstrual period is January 26th. I have been having cramps but no period. I even spotted 2days before the said next menstrual date. No period yet. Could I be possible pregnant? When can I do a pregnancy test
Hi ,
time to test yourself, you have a short cycle or you are irregular as you ahve a period starting on the 31 st and the next one on the 26 .. it is almost a week difference …
Good luck
i had wrote your name instead of mine sorry about that, but can u please reply to my messages if u have some free time
Hello,
I just noticed that the first day of my cycle was December 20. I have not had a period yet, but I have been bloated and feeling like I am about to come on any day now. Could I be pregnant?
hi,
i had my period on the 1st of Dec 2014 and was ovulating on 12,13,14, so on the 5th of Jan 2015 i took a pregnancy test and it was positive but now im have period cramps, is it possible that it was a false positive?
Hi , yes it is possible, some medication can trigger a false positive, the only way to know is to test yourself again, or do a blood screening… it might also be a right positive, but that you are currently miscarrying … you need medical advise if you cannot have an answer on a pee on the stick test.
Good luck
Hi.my last period was 27 dec 2014 and the next is supposed to be 24 Jan 2015 but I am yet to c it. Pls help me I have not had sex o
Hello, i had my period on the 28-1st of december 2014. i had sex on the 9th and 11th of January. it’s 25 and no period. had terrible pain in my stomach around and around the 14th to the 16th and i was told by the doctor that i had two corpus leteum after an untrasound. could i be pregnant with twins? i am also on the 28 cycle.
Hi,
corpus leteum , is yellow corp, the shell that is releasing the egg from your ovary not ovules,if your physician had doubt at the time that it could be a beginning of pregnancy he would had ask you more about your last period cycle. You indeed had sex during your fertile window, so you might be pregnant ! Test yourself !
Good luck
I am trying to get pregnant, I had my last cycle on 17th of January 2015. .When is the best time or date to have sex to enable me conceive
Hello.
I’m honestly a little worried about my period. My last cycle was around Christmas time, and I keep getting results from various calculators that I should be getting my next cycle around January 22 to today.
I’ve been having protected sex with my partner, and I had sex the Sunday after my last period was over. Since then, however, I’ve been experiencing a lot of stress from family and my partner. Not only that, my stomach has been hurting in the morning and sometimes throughout the day, making me avoid eating. I’ve noticed I have lost weight because of it.
I have not experienced any sort of spotting, nor do my beasts feel tender or different from usual.
Do you think my period is late because of stress or should I really be worried about other circumstances?
Hi,
stress can definitely delay your periods and even skip the cycle, it can also cause you spotting. Weight loss is another possible explanation for your period issue.
As far I am concerned, your weight loss is what is the most concerning here, and as it is due to your stress level, you should either try to eliminate the source or to have a visit to your physician for some advises and options.
Good luck
I had my last period’s first day on Dec 25, 2014. i stopped my contraceptive pills and had sex.. but we’re doing withdrawals.. if i continue my pills, i suppose to have my period last January 22. but now it’s january 25 and i haven’t had my period yet. please advise. am i pregnant?
Hi,
first of all, withdrawal is not a contraceptive method, it is playing the russian roulette .. you can get pregnant anytime doing this as precum contain spermatozoids. Second when you are getting out of birth control pill it can take up to 3 full cycles before getting to your natural cycle. You were artificially put on a 28 days one … if you are a natural 31 .. it will change , if you are naturally irregular, well it will be always random. If you pass 7 days after the moment you were expecting your period to start … test yourself, better be safe then sorry, especially knowing that you had unprotected sex.
Took contraceptive pills for more than a year. Just stopped last two weeks. Will i get pregnant if having sex during ovulation period.
Hi,
Everything is possible, but it is recommended to wait 3 cycles before trying to conceive after being out of birth control pill.
Goog luck
Hiii!
I had sex Dec. 31 my period comes every 24th of each month and it isn’t here yet.. Its the 24th.