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





Please, I had my menstruation last month 22-27 of July and I had sex on d 12 august I use postinor 2 and had another on the 17 August and I use another postinor two. Since then have been having pain on my nipple. Is it due to the drug or due to my guy always sucking my breast? Last month I had to use comnation 3 before my mensturation can come which have started since on the 19 august but have not seen my menstruation yet till now. Please what could be the problem, please look forward to the reply
Hi there, based on what you have said you have taken a lot of hormones in the last month to prevent pregnancy and then also a regular birth control. This can dramatically influence your cycle. I would anticipate by the time your next period comes along it will coincide with the end of your pack. You might even have spotting in between there. This could be why your cycle is late.
Hi my period is usually late but I haven’t had my period since last month and want to puke but i cant really puke because I don’t eat much. Is it possible that im pregnant?
Hi Alisha, if you had unprotected sex during your fertile period it’s always possible. I would recommend taking a pregnancy test.
Hi, I had my periods on 28 July and on the 13 August I had spotting. What should i think it indicates?
Hi there, it could be ovulation spotting as you might have ovulated later than expected.
Hi there, I had a miscarriage on the 15th of June and I saw my period on the 18th of July which lasted for 3days. I am yet to see my period can I be pregnant because my partner and I meet virtually everyday and I took a home test weeks earlier it says negative maybe there isn’t enough HCG in my urine.
Hi Sharon, if you had your period then you are able to get pregnant again as it means that you are ovulating again and thereby fertile. If you took a test weeks ago, take another test now and see the results. Good luck!
Hey. I had my periods on 10th July to 14th and had sex for 4 days on 15,16,17,18 but we are in august I am not seeing my period.
Hi Juannah, it depends on if you ovulated early. I would recommend taking a pregnancy test because you should have gotten your period at this point, especially if you have a relatively average cycle.
I had my period on July 8th 2019 and it is August 18 and I still haven’t had my period. Is it possible that I could be pregnant when is the best time for me to take a pregnancy test.
Hi Savannah, it’s possible that you are pregnant if you had sex during your fertile period and at this point you are over a week late so I would take a test.
I had my period July 13th thru 17th and then again August 1st thru 4th. Keeping with my 21 day cycle a period should be coming soon but could I be pregnant already.
Hi Dorie, if you had sex during your fertile period then you could be pregnant. Take a pregnancy test if you are late.
I saw my period 23rd of July, n till now is August 18 I haven’t seen it. Pls what should I do?
Hi there, you should have seen your period around the 20th of August which is before your comment. I would anticipate that you should have seen it by now if you were not sexually active during your fertile period.
I had my period on June 23rd to June 30th
Around the 4th of July had intercourse
Got my period on on July 19th to July 24th
Had Intercourse on August 10th
I haven’t received my period just wanted to know if stress might be the case
Hi Amber, it could be due to stress because you should have seen your period and it doesn’t appear that you had sex during your fertile period. If you are concerned take a pregnancy test to reduce your stress if this is adding to your stress and try and relax (on a general basis, find something that relaxes you).
Hey my cycle is 28days I had sex June and I saw my period that june and July 9th my period came out its August 12th and no sign of my period coming out what could be the issue I haven’t had sex since July
Hi, well looking at your post you had your period July 9th, and then you say you haven’t had sex since July, so if you had sex in July you were likely during your fertile period and you may be pregnant. Either you have gotten your period already or if not take a pregnancy test.
I saw my period on the 7 of July to 12 July, and I had sex on 31st of July and I took postinor2 on the 1st of august. My period lasted for only 3 days, am I pregnant
Hi Faith, emergency contraception can affect your upcoming period. So this might have been accurate for this cycle. I would wait until the next cycle to see if it returns to normal.
I saw my period on 29 June and it stop at July 2nd and have not see my period. What will I do?
Hi there, have you taken a pregnancy test? If you have and it’s negative consider anything stressful that has been going on in your life. If nothing, then maybe see your doctor, especially if you are usually regular.
hey, I went to my period on the 2 of June and 29 June again and they stopped on the 3rd of July. Now it’s August and I’m waiting for my period. Do you think I may be pregnant I had sex on the 11th of July is it possible that my period will come late august?
Hi Zama, the 11th of July would have been during your fertile period so I would take a pregnancy test.
Hi please, I saw my period on 1st of July. Until now I have not seen it. I expected to see it on 1st of August but is not showing up. Please help me, I made love with my partner of 14th of July.
Hi Jane, your fertile period would have been July 11th-July 15th, which means you would have had sex during that timeframe. If you haven’t seen your period yet, take a pregnancy test.
I had my last period on 29 of June, which lasted four just 4 days, which is on the 2nd of July. I had sex on 13th and on 27th of July with my husband, and now I saw my period on 3 of August, am I still pregnant. plz reply
Hi there, if you got your period you are generally not pregnant.
I got my period on July 4th n it stopped on July 8th, I still haven’t got notice yet what are my chances of being pregnant
Hi Marie, did you have sex during your fertile period which would have been from the 14th-18th of July. If you did then take a pregnancy test.