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 had my last period on the 10th of March. Now I had sex on the 27 of March and we checked the condom and it wasn’t broken but last Saturday night we had sex as well and the condom broke so Sunday I took a morning after pill but I didn’t have my period yet. I’m so scared to be pregnant now can I be? What do I have to do now?
The morning after pill may have delayed your period; you may not be pregnant. How many days are in your menstrual cycle? When is your next period due?
Normally like 30 so I’m 5 days late I did a test I’m and it was negative but still don’t have my piriod
Sarah, most probably the pills must have delayed the period. Also, pregnancy test should be taken after at least 10 days of missing a period, for better accuracy.
If my menstruation starts 12th of March & lasts 4 days while the next period starts 10th April, how do I calculate the length of cycle?
You have a 29 days cycle. To get this number count March 12th as day 1 and do not stop counting until you get to April 9 – you will count 29 days. So it takes 29 days before your period started again on April 10.
My last period was march 14th-18th 2016 but they are usually irregular and I had unprotected sex on easter march 27th 2016. I have been experiencing a lot of cramps and back pain and I have felt bloated for a week and a half straight. I took a pregnancy test April 10th (the 5days sooner riteaid brand), it was negative. Could I still be pregnant?
Hi Shay, you can try taking a pregnancy test after 2 weeks of first one, to make sure, if you have not got your period till now. If it is still negative, then consult a doctor. ATB!
My last period was on Feb 26 then the next menstruation was on March 30. How many days are in my cycle and what is the best time for getting pregnant. I’m celebrating 2 years of marriage and I want to have a baby.
It is possible that you have a 33 days cycle. All things being well, you’re likely to be fertile from April 16 to 20. Your next menstrual period is expected to start on May 02, 2016. Good luck.
Your next menstrual period is expected to start on March 30,2016.
You next most fertile period is March 14,2016 to March 18,2016.
hi my 1st day of my last period was 3/3/16 . i had brown discharge the 4/1/16 only lasted that day . its is now 4/11/16… my last period was very light an only lasted 4 days …i had really bad cramping last night .. but went away today no pain an no blood .. i took a home pt an it was negative and advice about these issues ??????
Hi Amanda, please see a doctor and take a blood pregnancy test. All the best!
Hi, my last period started March 7, 2016. I am 4 days late and I am having frequent headaches and nausea. I did a home test but it was negative, when should I try and test again?
You need to re-test at least one full week after you’ve missed your period. Wait a few more days.
Pls my first day of my last period was on 15 march 2016 and the last day was 18 march 2016.I had sex on 25 march 2016.can I be pregnant?
Hi Ayebea, yes there are good chances. But please wait till next period before reaching any conclusion.
My last period was on 31 March to 2 April 2016, my ovulation starts on 22 to 27 April. I had sex with my husband on 10 April, please when is the right time to get pregnant?
The most fertile days in the cycle will be at least 3 days before, during and some days after ovulation. This will be the best time for you to try and conceive. Sperm will survive for 3 to 5 days while the egg will last for 12 to 24 hours. You are fertile for about 5 to 7 days.
Hi Emily. My name is Manita. I expected my period April 7 2016. I am now 3 days late. I felt like my period was coming but it still hasn’t. My period is usually like clock work. This morning I went to the bathroom and when I wiped blood was on the tissue. I figured I had started but no blood after that no trace or sign of blood. Could I be pregnant. I’ve taken approximately 10 pregnancy tests which were all negative. I have 1 son he’s 4 and when I found out I was pregnant with him, the situation wasn’t anything like this (unpredictable). Please help, I’m very in tune with my body now. I’m questioning if I really am. I’ve been feeling bloated like I’m coming on for about 4 days but no period. I don’t know what to do. Please help. Isn’t it too late for that blood to have been implantation? I’m so confused. Oh BTW, we are ttc but never expected this.
Hi Manita, pregnancy tests are recommended to take around 10 days after your supposed period date. So you should take one pregnancy test now if you have not got your period already.
Pregnancy signs might vary greatly with different children as it depends on many factors (first pregnancy/age/food habits/mental and physical conditions etc). All the best!
Average cycle days 29.
My Period Came on March 10,2016 and Lasted for 5 Days. I began to spot for 3 days on April 2nd,3rd, and 4th. My Period Tracker says my Cycle should Start on either April 8th or the 9th.
Please Help! I Haven’t Taken a pregnancy test.
Hi Daliah, if you have not had your period by now, please take a test.
i had a period on march 17 2016,and have an sexual intercourse on march 28 2016 and april 05 could i be pregnant? my average cycle is 35 days
Hi Dave, yes there are good chances. Although, please remember that everytime sex does not result in pregnancy. All the best.
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I had my last period on 23-25 March. On 8,11 I had sex with my boyfriend and then again on the 21 and 22 March. And last month(March) I didn’t have my period. I was feeling tired and sleepy for a few days after that and my breasts were fuller. On 3-5 April I had my periods and today(9) have been having cramps feeling funny.i never took any test when I got my period.what could be the problem,m I pregnant?
Hello, if you are sure that you had proper period during 3-5 April and it was not some other kind of bleeding, then most probably you are not pregnant. Are you having any other unusual experiences too?
Birth control might be a reason here. If you are still feeling cramps, please see a doctor. All the best!
I had my period the 21st of July which lasted 7 days, on day I had pull out method sex. I got back with my ex on the 2nd and had intercourse unprotected 3rd, 4th,5th , and 6th. Chances of pregnancy from sex on day 8?
Brady, sorry your question is not very clear. If you are pregnant and want to know on which date it happened, there is no way to know that without a medical test.
Had a light period on the 18 th feb 2016 then had another period on the 5 th March notmal one this time had a few headaches been sick and white milky discharge 5 test negative what should I do next thanks x
Hi Sarah, have you got your period in April by now? If not, then please take a pregnancy test again. All the best!
Hello I am 6 days late and my last period was March 3, 2016 and i took 6 days.
Please i wanna know if i am pregant..
Hi Hannie, 6 days late is not uncommon. Please wait for 4 days more and then take a pregnancy test. Late or missing periods can be because of many reasons other than pregnancy too- like a new medication, a sudden change of diet, heavy exercise etc.
I had unprotected sex on 9th March and after I missed my periods on 20th of march, I tested four times and two of the were negative… Home tests were positive…I again got my periods on the 3rd of April which are heavy and cramps for five days now…. Could I be pregnant or what could be happening to me?
If you’ve tested positive you need to start booking visits to your OBGYN. It is possible to be pregnant and still have a period. You must see your doctor.