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





My girlfriend had her last period 10 FEB 2016 and was supposed to have the following one on the 9th of March 2016. We had sex on 8th March and pretty sure – 200 % i did let anything inside. Now she’s delayed 12 days and we tried 3 tests that were negative.
She had a cesarian last year September 2015 and also suffered UTI…Can you help on that ?
You have to ensure that the test is taken at the right time. You can get the most accurate result if you wait at least one week after missing your period. In addition, the result might be even more accurate if the test is done first in the morning as the urine is far more concentrated at this time.
Hi. Your most fertile days would have been March 7-12. Having unprotected sex can always result in pregnancy. If you are concerned you should take another test and talk to your doctor. Best wishes.
I saw my period on the 3rd of March 2016, and I made love to my Hubby on the 13th, 14th, 18th and 19th of March. Is there any chance of me getting pregnant within those days
This depends on whether you were ovulating or fertile during those days.
I had unprotected sex with my boyfriend on February 25. My period came on the next day and lasted 3-4 days. Had unprotected sex on March 7, 11,16 & 20th. My cycle is 28 days. What are the chances of me being pregnant? Really need to know ASAP!!!!
You were fertile from March 9 to 14 so it;s possible that you conceived.
I had my period around the 10th of Dec 2015 and finished it around the 14 Dec 2015. I Had sex with my ex on the 19th of Dec. I took a morning after pill on the third day but not too sure can’t remember exactly. I had sex with my current BF and had what looked like a period around the 5/6 Jan 2016 and I found out that I’m pregnant on the 7 Feb 2016. I’m 10 weeks and 6 days today. Could this be my ex’s baby or my current BF? Please help I’m going crazy.
It’s your ex’s baby sorry
I have the same problem as you. My bf and I had sex last August of 2015 and then I had my period for one day. After that, I had sex with another guy in October. I found out this Feb 26, 2016 that I’m 23 weeks and 6 days pregnant. Is it my bf baby or the other guy?? Please help me to find out.
Since you’re over 23 weeks pregnant then it is highly likely that you conceived for the other guy.
So it’s the other guy’s baby, right??
It is highly likely. Can you recall the date of your October and September periods?
My last period was september 13, 2015 and then on october I don’t have period and so on,,
Had my period february 17th. Still not here. I should probably test, right?
That depends. When you are a teen, cycles tend to be whacky, and not very reliable. You can have you period anywhere from two weeks before to two weeks after your supposed time, and have it not be a worry. Your cycke shoukd become regular as you mature, but if not, it wouldnt be a bad idea to get checked out. 😉
Wouldn’t hurt.
I had my period on the 14th of February, and I haven’t seen my period till now, am I pregnant
Me too. I’m taking a blood test tomorrow. My nerves are too bad to wait any longer.
Hi. I had my regular period Feb 12 and I had sex Feb 21. I got another period that was mild – not heavy and it lasted a few days longer. Can I be pregnant? I was scheduled to have my regular period on March 10 but it didn’t show.
I had withdrawal sex 4 times on the 1/2 of March. Last period was Feb 17th and lasted 5 days. I normally have a 28 days cycle. Should I be worried yet? I’ve had period pains on and off since the 9th.
Could I be pregnant? My last period started on the 28th of Feb and was done by the 3/4th of March. On the morning of the tenth I had severe cramping, which is usually a side effect when I ovulate on the right side as I have a cystic issue there and was prescribed a pain killer from the dr. to deal with the pain during ovulation; however I’m not sure if I actually ovulated that day or my body was just preparing, I was already having my ovulation pains and thought about canceling but my boyfriend and I ended up having unprotected sex that same night of March tenth, and again on March 13th. There was one additional act on the evening of the 16th. It’s been on my mind whether I could have gotten pregnant as I’m not on birth control, though I know the chances of actually conceiving are between 1/4-1/3, even given it being the perfect time. We’re not TTc but I’ve been noticing symptoms. Within days I was having severe headaches and feeling more hormonal than usual, and I wonder if these were really just ovulation symptoms. If I assume I ovulated on the 11th then I’m now 9dpo and have extremely extremely sore breasts which is not a common pms symptom for me, as my primary symptom is extreme moodiness, which I can’t say has been amplified. I’ve also been a bottomless pit the last week or so with extreme and random protein cravings (I’m a vegetarian so for me that has meant getting hard core cheese and fried tofu munchies) and getting breakouts on my face and body (maybe it’s the fried tofu! :P). Only very soon after having the sex did I have cramps but haven’t had significant ones since. Part of me is hopeful, but I also wonder if it’s all in my head. Please help!!
Hello there, yes they may be due to a pregnancy. I would suggest that you wait for your next period date and see if you get it or not. Also, the ovulation days are the ones where you have the highest chances to conceive, but it doesn’t mean that unprotected sex on any other day can’t result in pregnancy. Until you want to get pregnant, please always always use protection. All the best!
So I had my cycle on February 7 and I’ve been taking pregnancy tests which show negative but yet I haven’t gotten my cycle for March yet and I feel pregnant. I’m ALWAYS 21 days to each cycle and I was supposed to have my cycle on March 1 but I haven’t since February 7. So could I be pregnant and it’s not showed a positive result yet?? How much longer should I wait to test again to get a positive result??
If you were pregnant the results would show positive by now. Read our link on how to improve your chances of getting pregnant http://womanjunction.com/how-to-get-pregnant-guide/
I started my period on 4 March and finished on 8th March. My cycle is 30 days. When is my fertile date?
Hi. Your most fertile days would be March 17-22, April 16-21.
Hi my period date is always the 16th of every month but now i have missed it and it is now the 20th of march would i be pregnant ?
I seen my period 7 january 2016,4 of february and 7 of march 2016.when is my fertile day?
Hi. You are most fertile March 18-23. Good luck!
I have not had my period since January 30 and I have not gotten my period. I took a pregnancy test a week later in March but it was negative. Could I still be possibly pregnant?
Hi Zoe. You should contact your doctor.
Hello I have problems to calculate my cycle, my first day of my last period was 14-02-2016, and I had sex on 01, and 03 and 14 of March until now I haven’t get my period and I’m worried never been pregnant before, please help me do you think my period is late or??
Hi. Your most fertile days were March 12-17. It does seem that your period is late. Unprotected sex can always lead to pregnancy. You should take a pregnancy test and consult with your doctor if you are still concerned.