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, the first day of my last period was oct 18th, this past month I started taking ovaboost to help me with ttc…anyone ever tried them? Haven’t had a period yet
What does TTC mean and where do I get it
TTC means Trying To Conceive
Hi I personally never tried them but you should discuss with your physician before or while taking any medication so you can have the right answers to your questions.
Good luck
Hi so I had my period September 31 thru October 2nd and again October 16 thru October 22nd . My next cycle was suppose to come on November 10th but it didn’t it was 8 days late and came on today November 18th, it is very light and don’t really seem normal I dnt gave cramps ir anything. I took a pregnancy test when it was about 3 days late which came back negative. And besides it coming on back like it did the previous months my cycle is pretty normal and my average is a 25 day cycle and I’m wondering is there a chance I can be pregnant?
Hi,
If you did your test as per the label, being 3 days late there is no reason for you to believe you are pregnant.
Good luck
my menstrual cycle start on Oct 31 to Nov. 4. then we had unprotected sex with my boyfriend on November 5 and 6. is there a possibility to get pregnant in this period?
Hi… I’m just not sure.. I had my period on Oct 26… And stop Nov 3.. and I had sex Nov 6.. and I’m not sure what to expect.. lately I’ve been blah pukey kinda breastfeeding been hurting.. and it said I was ovulating Nov 7-11… possible I could be pregnant? This would be my second baby. Or would it be too soon.. I’m not suppose to get my period till Nov 23..
Hi,
well test yourself once your periods late but hormonal disbalance due to your breastfeeding could give you these symptoms as well.
Good luck
my last period was from oct 9 through the 15. I have been trying to get pregnant. I haven’t started my period yet, technically I am 4 days late. could i be pregnant??
Hi, I had my period last 10/13/14. And had unprotected sex on the 10th day of my cycle 10/22/14. I took morning pill on the 6th day after having that unprotected sex. And last 11/05/14, I believe I had spotting and it lasted for almost 5 days. The color is like pale red. I’m wondering if I’m pregnant. I had a 2 yo son, I’m 35 yo and still dont have any plans of having another child. Please advise. Thank you.
Hi , the only way to know will be to test yourself, the emergency birth control is not a guarantee … but help. If you dont plan to expend the family maybe you should have a talk with your physician for long term birth control solution.
Good luck
hi I have been menstruating for five days since I started menstruating please I want to know if its normal or I have a problem. Again, I had my menstruation on Nov 2nd and on 6th I had sex is it possible for me to become pregnant.
Hi ,
it is rare but yes it is very possible if you had 2 ovulations in the month. When you have unprotected intercourse or have an incident that compromise the safety of it, you have to take an emergency birth control pill within 72 hours to avoid having these worries, by now … you will have to wait to see if your next periods are late.
I had my period on October 8 then it went off like it was supposed to then I started spotting on the 23 till the 26 and then I spotted on the 31 and 1 and my next period was supposed to be on 1. What does that mean ?
Hi ,
spotting can happen, it is not an uncommon or dangerous thing. Gym, new diet or change in life style can cause them. That does not mean also that you are pregnant , if you are taking a birth control pill it might be time to visit your physician to change it , progesterone have a known tendency to cause that. If not by your next cycle, you will be settled.
Good luck
Hi. I had my cycle on Nov 22. 2015 – Nov 28 2015 and I had unprotected sex on Dec 5 2015 and I haven’t seen my cycle it suppose to come on Dec 20 2015 but I’m 7 days late and it still haven’t came on. I just got off birth control in July so my cycle returned in November. What can be the reason?
Hello ,my last period came out on the 12th of October last month, and this month of November, it came out on the 10th. so I want to know when I will ovulate.
Hi , the rule of thumb is pretty simple the first day of your ovulation is the day 1 of your cycle, your fertility window is between day 12 and 17 for regular cycle and day 10 to 17 for irregular cycle.
Good luck
I missed my bc pill on the 27th of October which would be when I ovulate and I had sex now my period is one day late but I’m getting negative tests. What sould I do
Hi , skipping one pill on the pack have no effect on its efficacity but don’t take an habit out of it. take it as soon you realize you skipped one. Dont double the dose if you notice the missing pill only the next day discard it. and protect yourself with a condom for 7 days just in case …
Good luck.
Hi, The first day of my last period was September 30th and lasted 3 days…it is now Nov 12 and no period I had cramps last week but no signs of blood…I have taken 2 test both were negative however the last 2 times I was pregnant I didn’t find out til I was 12 weeks only because I had gotten really sick and had to go to er but both times o took 5 text and all showed negative before I ended up going to er…The only problem is I miscarried with the first one shortly after I found out I was pregnant and with my daughter now I found out I was pregnant with her at 12 weeks went to the doctor and I was already starting to dilate I had to have a cerclage placed at 13 weeks…so I would like to know what’s going on due to if I am pregnant I may miscarry at anytime like before
Hi , with your history, I really recommend you to figure this out with your physician, he will do you a blood screening, blood screening never lie …
Good luck
Hi I am 41 days late on my cycle but I also have the Nexplanon in my arm what do you think is wrong my cycle was every other month so I would be off a whole month
It is possible to skip a cycle and especially with this progestative method you might have no or very light periods. If you are worried about it have a chat with your physician that can reassure you that it is completely normal or investigate further if it is not !
Good luck
Hi. Im really anxious to know if theres a possibility that i am pregnant or not. My last period started october 2-9 2014. Yet i havent get my period and i was expecting it the 3rd of this month. After i had my period my boyfriend came inside and also he did days before i expect my period. We dont use protection neither i do pills. I want to knkw when am i going to be able to find out if i am pregnant or no even though i tested myself twice already and came out negative.
Hi ,
if you are trying to conceive you are not in your fertile window whatsoever , if you dont … you are playing with fire ..as there is always a change to get pregnant. Skipping a cycle is normal and harmless, but you should be more responsible and prevent you this stress, because just the stress related to the delays of your periods can delay or skip them. Also gym routine, dieting , nre job … can lead you to skip cycles.
Good luck
i had unprotected sex on my 8th,9th and 11th day of my ovulation period.can i get pregnant?
Hi my first day of my period is september 26 ended at october 02 now my next mentration is October 26 but still didn’t came now I take a pregnancy test and its positive I want me to know if how many weeks or month that I’m pregnant please answer me wait for reply
The day 1 of your pregnancy is the day one of the last period you had, meaning in your case september 26 th !
Your due date is then January 15 th 2015, congratulations !
I know this is a year old and hope pregnancy went well but I saw your post about wanting to know due date and I’m confused to how you said you’re last period was September and she gave you a due date in January!?! Thats 4 mths. Sorry just confused by her response
.Hi period is irregular and it is confusing me i had my peripd on Sept 17 and it came on Oct 25 and i don’t know when i am safe or not my genecologist has been trying to put me on the pill now but i am afraid to go on it and it is making my relationship with my boyfrd hard because i dont want to get pregnant and i want to know how to calculate my safe period.
P.s plz i will like to know when it is safe to have sex this month of Novermber thank u very much
Hi , without any birth control, it is never safe to have unprotected sex ever. The birth control pill is a good idea to become regular, you will have your period settled like a clock and will not have pregnancy surprises, if taken correctly. There is no reason for the birth control pill to be a problem in your relation with your boyfriend. Getting pregnant might become one … Please be careful. There is also other solution if you think that you might forget to take the pill you can have an injection of depo provera once every 3 months or under skins inplant good to up to 5 years, discuss your options with your gynecologist.