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 period March 15 we had pull out method March 25 at 3 am then that night I had spotting, continued 26,28 and 30, by March 31 feeling full but hungry, cramps, a little heavy lower stomach, sleepy at day but can’t sleep at night, got diarrhea once then bubble movement on my stomach , sneezing , a little hurt at pelvic sometimes what is this??
Your ovulation started day after you had ‘semi-safe’ sex. No, there is no way that I can estimate if you are pregnant or not. You had an intercourse on the peak of your fertile period, but your partner didn’t do anything- I can only speculate that you are experiencing symptoms of the menstruation. Specially when you describe all the hormonal ‘symptoms’ connected with the PMS like the hunger, bowel movement and so on.
Hi, need your advice pls, I had my period on 27th February, I haven’t seen my period till now,29th March. But for like a week now, I am experiencing pain from my abdomen, my breast shows the sign, I checked my urine this morning to see if I am pregnant but it shows negative. Kindly advice.
The urine test can be false positive and false negative, and in many cases of the early pregnancy it can be false negative. It is way too early to say if you are pregnant or not, because if you are – you are pregnant maybe less than 2 weeks.
Hello,
I had my cycle March 3,2015.. I had unprotected sex with my fiancĂ© in my fertile window March 15-17 and even a few days before and after…the following week I suffered from nausea, migraines, bodyaches, and fatigue… Now the symptoms have stop except for the bodyaches and fatigue… My fiancĂ© has had and amazing increase in appetite and he is extremely fatigued and oftimes sleepy. I took a test , however it was negative, could it be that I tested too soon? Could it be that I am truly not pregnant.
I think it is maybe too early for the test or for any conclusions. The nausea and fatigue can be caused by other things, specially because it is the end of the March dn we can expect spring effect, allergies, colds and so on.
Wait for a week and then repeat the test.
My ovulation period ended on March 22, 2015. I had sex with my boyfriend today march 26. Could I get pregnant?
If you have the irregular periods, prolonged periods, then you can get pregnant, but if you are absolutely sure that your fertile period ended 4 days before having sex then you can’t be pregnant.
I saw my period on the 18th of February and then i experienced light bleeding on the 8th of march i took a pregnancy test and it came back negative. it’s now the 26th and still no period. Am i pregnant please help me. Anyone!!!
You may had a prolonged period or slight hormonal disbalance. I would say that it maybe too early to conclude anything by taking tests or doing calculations.
If you had an ovulation around 8th and an intercourse at the same time there is a possibility, but just having sex at the certain date doesn’t guarantee that you will get pregnant.
In any case visit your doctor and you will get to know everything that troubles you.
Hi, I wanted some advice before taking a hpt. I had my last period on 2/27/15 and it is expected to come on 4/1/15. I am very irregular 33 days. I had sex with my boyfriend on the 3/15/15 and he ejaculated in me twice and again on 3/20/15 where he also finished inside me. So what is the possibility of pregnancy? Thanks in advance!!
Yes, the pregnancy under the mentioned conditions is highly probable but the test won’t be accurate in such a short time. It is way too early for taking any tests because hormones are still very low.
In short, the possibility of pregnancy is very high.
I had my last period on February 16,2015 and it’s now March 26,2015 and I haven’t had my period yet.
I had sex on 19 Feb. Don’t remember when last I had my period. Period usually last 3-5 days. Now I have cramps on my right side. No period yet. Want to get/be pregnant
You could be pregnant, but you forgot to mention the length of your period (28 days, 29, 30…) and your age, so I can’t tell you anything based only on this. Cramps could be from some other reasons. Visit your doctor if you are worried because test is not always accurate in the early stage and unilateral cramps may be an indication of an ovarian inflammation.
Hi. I got my period Feb 1 for 5 days then again on Feb 25 . I am now late. Took 1 test 2 days let and it was neg. Took another one this morning and it to is neg. No symptoms of pregnancy.. but cramping and bloating and increase in CM which seems to be thick and white..maybe slightly chunky. With the cramps for last 2 days keep checking for AF as i feel it is right around the corner b ut so far nothing. Any advice as to when to test again or should I forget it and wait for AF?
I think that by now you should get your period and if not then I am strongly advising you to visit your doctor. As you said you are having cramps, so your period should came by now.
Hi, my last cycle was Jan. 31st. I’m pregnant but I just can’t figure out when I conceived because I have an irregular period. Please help I had sex Feb. 10, 2015 with my bf and on Feb. 15 with my ex. I really need help
If you have the irregular periods then it is not possible to determine when exactly you could get pregnant. If your period lasts less than 28 days it could be your bf, and if it lasts longer than 28 days it could be your ex. There is no way to know without the science of course.
I had my period last month normally from February 22- 26th.. Usually my cycle is between 27 to 30 days depending if I had sex or not. This month my period has not come, I am a little bit concerned, but I am sure I am not pregnant because I didn’t have sex between my last period and now…so why is it delayed?
The menstrual cycle may be delayed due to many reasons.
Sometimes we can blame the disbalanced hormones or the residual ovarian cysts from the previous period. Even a mild cold or a flu can be a stress factor strong enough to delay your period. The other reasons are the anemia and psychological stress.
Don’t forget that the period can be anywhere between 24 to even 40 days. If it surpasses 40 days please visit your physician or gynecologist.
Pls if one is about a month pregnant and does not want to keep it what can she do
I can’t advise her what she can do. My personal inclines are against abortion not only because the social stigma, dogmatic dribble, moral questions and the fact that I believe that a human life begins in a single cell.
The abortion is a medical procedure and it damages uterus but also does a huge mess with the hormones and psycho. She may end with the inability to ever produce a healthy child ( or any child ) in the future. If the fetus is so to say ‘wrongly set’ the nature take cares for that ( usually the early stadium of the pregnancy ) as well as it take cares of the possibility that mother body can’t endure pregnancy.
Spontaneous abortions are not the same. Unfortunately they are tragic, sometimes medicine can help but in many cases there is nothing to do about it.
I can advise her to give a life to a baby and set an adoption process. You can see how many people here are trying so hard to get a child and they are failing. She has an opportunity to make some sad family very happy; no human life is just an accident.
I had my period on January 8 and next on Feb 12 both lasted for 3 days. When I checked my menstrual calendar, I should have my period on March 19. Is that normal that I still do not have my period? I have had unprotected sex with my partner but never on my ovulation and fertile days. I am feeling the same symptoms before having my period (sore breasts, cramp, backache) we tried doing it last time and there’s blood when I wiped it. I am a bit under stress as well due to work and some stuff. Should I take test now? or wait till when?
Thank you.
Hi, having unprotected sex, fertile window or not, it is always a gambling. Yes it is more then time to test yourself, to either confirm a pregnacy or to releive you from at least one stress. It is not uncommun to see changes during stressful time, skipping a full cycle is not drmatic as well. If it become reccurent, you should have your physician looking at it . I also strongly recommend you to discuss with your partner about choosing a reliable contraceptive method to avoid such questionning in the future,especially if conceiving in not part or your plan for the moment.
good luck
My fiance had her first period day on Feb 20 and lasted for 5 days.We had unprotected sex on Mar 1 and Mar 15th.When is she expecting her next period?She don’t recall if she’s regular or not.Kinda anxious since I had seen such early signs of pregnancy yet it is similar to her PMS which are subtle.Need help ASAP
Hi, without knowing if she is regular or not there is no way to predict her next periods. But, What can help you is that it takes 14 days after the conception to trigger a positive pregnacy test. So counting since the 15 th … add 14 days before testing your girlfriend.
Also to avoid such worryness in the future you two, shoud discuss about a reliable contraceptive method, as you had intercourse during her fertile window, which is … playing with fire if you are not trying to conceive.
Good luck
Pls i need help,I saw my period in Jan 19th and i had sex with my husband during my ovulation time,i saw my period again in Feb 10th 2015 and i was feeling sick,tired even throw up. To my surprise I saw my period again in March 6th,it came for only 2 days still feeling same way I felt in feb. Can i be pregnant? Pls i need help
Hi,
some women will keep having bleeding looking like periods on the first trimester .. sometine longer. Did you test yourself for any pregnancy or as you had period you assumed that you were not pregnant, which would had been a normal reaction ! Test yourself with a clearblue test that indicate also for how long you are pregnant, it will help you in case it is positive, to track your due date !
Good luck
Is it possible to have sex and month after you get your period and it lasts normally and be pregnant? And not to get a menstruation month after you got?
There can be some strange bleeding, but it’s not normal. It is usually a strange discharge or a shortened menstruation. In any way, it should be much different than a normal menstruation.
In order to get pregnant you have to have sex on certain days, when you are fertile. It is not even 100% sure that you will get pregnant if you do so- not every egg is healthy, hormones could be in disbalance, your ovary may discharge the actual egg in the abdominal cavity instead in the ovarian tubes…
If you are experiencing any difficulties you should consult a doctor.