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 went for depo-provera on 17 on July 2015 and didn’t go for the next shot. I got my menses on 14 September. My cycle is 28 days. I had sex with my guy on 8 October and took Postinor 2 the next day. I tested with strips and was negative. I had a drop of blood on 18 October. Please help me can I get pregnant…I’m very worried.
Since you took the Postinor within 24 hours, it’s possible that you’re not pregnant. You can take a pregnancy test at least one week after you’ve missed a period just to be sure.
I had my period on july 26 I then miss my period on august and on august 19 I had intercourse with a guy I had my period on sep 2 I got my period and I got back with my boyfriend on sep 19 I had intercourse with my boyfriend I went to the clinic I am pregnant she says im 7 weeks and a day but my cycle from july to sep was 37
Hello ladies,please help me out,i had my period on the 25th September…and we have been having unprotected sex.On the 18th this month he came inside me…Is there a possibility of me being pregnant?
Your chances of being pregnant depend on whether you were fertile on or around the date that you had sex. In any case, 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. The urine-based home pregnancy tests offer great accuracy.
Hi my name Minnie I have a 28-day cycle my last period was on Sep-24-15 my next period was post to start Oct-21-15 but it’s not here yet. I have been experiencing dizziness for a week when I wake up from naps in overnight. Could I be pregnant or is it too early to tell?
It may be too early. 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. The urine-based home pregnancy tests offer great accuracy.
My periods are usually regular either 24-day cycles or 28-day cycles. My last period started September 24. When would I be most fertile? Is there any way I could be pregnant now? When could I take a test?
With a 24-day cycle you were fertile from October 2 to 6, 2015 and a 28-day cycle made you fertile from October 6 to 10.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. The urine-based home pregnancy tests offer great accuracy.
I saw my period last since on July and since then I haven’t see my period again and last month I went for test the result come out negative and up till now my period have not still come out. Please, what could be the problem or cause of that?
Your period may be delayed for other reasons. Please read this link for more information http://womanjunction.com/8-mess-period/
Hello…my periods were on the 23 September 2015. and now I have not seen them yet and they were supposed to start on 21 2015..Am I pregnant?
You can get the most accurate result if you wait at least one week after missing your period before taking a pregnancy test. 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. The urine-based home pregnancy tests offer great accuracy. This accuracy will depend on several factors such as how early the test is taken, if the instructions were followed closely, when ovulation occurred in the cycle as well as how early implantation takes place, and the sensitivity of the test.
I had my period last Sept 18,2015,I usually have a 28 day cycle, now I am six days delay on my period and this morning I took a hpt and the result is positive,but I get confused cause the other line is lighter and the other one is darker.I repeated it again and the result is the same.
Am I pregnant?
Hi, Yes you are pregnant a negative pregnancy test means only one line, even if the other line is faint it means you are pregnant.
Hello
My last period started 19th-10-2015, usually 28days menstr cycle. plz when is my most fertile days? I want to conceive…..
My period came 10 days late this month and lasted only 2 days. Was that a period?
Yes, it can be considered a period.
Mu menstral cycle keeps changing what might be the course?
Hi. My last menstrual period is September 20, 2015 and until this moment I have not menstruated? Please let me know until when can I wait or is there any chance that I’ve pregnant?
Thanks
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. The urine-based home pregnancy tests offer great accuracy.
Hi my periods are regular but I haven’t got my period for this month it’s supposed to come on October 15, 2015 but I haven’t got it yet. What am I supposed to do!!!
If you are sexually active and think you may be pregnant then you can take a pregnancy test by tomorrow. If you don’t think that you are pregnant then your period may be late because of other reasons. Read this link for more information on the causes of a missed period http://womanjunction.com/missed-menstrual-cycle/
Hi Roopa here; actually my periods dates are fluctuating. This month I got my period on 1st and we had sex on the 4th day of my period. Can I get pregnant?
Yes, it is possible to get pregnant during a period. An egg can survive in for about 24 hours after it’s released from the ovary. If sperms are present in the fallopian tube at that time, one of them may fertilize the egg and lead to a pregnancy. Sperm can survive in the reproductive tract for up to five days; it’s possible that the sperm may still be hanging around during ovulation, ready to fertilize the egg.
I had my period on the 12 September 2015 and this month I had it on the 16 October 2015. When will be my most fertile days?
Based on the dates give, you had a 34 days cycle between September and October. If your periods are regular you will be most fertile from November 03 to 07, 2015.
I started my period on 7 September (4 days). Had sex on 25 September my this month cycle is 32 days I had period on 8 October (3 days) but is lighter hope I can be pregnant.
It is possible that you conceived and that you experienced implantation bleeding. Good luck!