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 sex on the 8th of July (protected but the condom got burst). I used Postinor 1 (2 tablets) and Ampicox (2 tabs) within 30 minutes that this happened. My due date is 20th of July, two days time I’ve not felt the pre-menstrual cramps and I’m scared, hope I’m not pregnant.
Emergency contraceptive methods pills can delay your period by up to one week after you normally expect it. If it still doesn’t come within three weeks, take a pregnancy test.
HI Steffy,
My last period was from June 16-23. I had unprotected sex with my boyfriend on July 5th twice but he “pulled out.” My period was supposed to start on July 12th but nothing has happened. Should I be worried? We only have sex once a month because of our locations. Last month I had sex with him a week before my period and it came then. How long should I wait until I should be really worried? I’m now 5 days late and nothing is happening. Should I get a test?
Yes. I would definitely recommend you get a pregnancy test soon. I do not know the length of your cycle so I can determine if the chance of pregnancy is high or low. But being that you are late I would suggest getting a test.
Hello, you could wait up to days to allow for your menses. However, as mentioned above, depending on the duration of your cycles, if it’s a 28 day cycle, you may be close for ovulation, and therefore, conception, despite withdrawal method. Usually, fertilization occurs at best within 2 days of ovulation. The sperm may be active for up to 5 days. Also, if you are on oral contraceptives, the possibility of fertilization is 0.02%. Other factors for delayed menses, depending on age, and/or other medical condition, are stress, anxiety, poor nutrition, hormone irregularity, medications, ectopic pregnancy. Please don’t be alarmed by these comments. You may do the home pregnancy test if you are 1 week late, and/or consult your primary care provider. Thanks
Hi, I am trying to have a baby. My period started July 14 and ended today July 17. When is my fertile period and when would my ovulation day be? Thanks for all the help.
When will my period start again
Hi Steffy. Me and my husband been trying to have kids since 2010. My last period was on May 15 to 21, and until now I didn’t have my period. Does this mean I’m pregnant? Please help.
Hi Girly. Since you’ve been trying for so long there may be underlying issues that are affecting your ability to get pregnant. You may need to consult a doctor to determine if you have fertility issues. To increase your chances, you also need to track your fertile days and ensure that you have intercourse on those days. It is difficult to say if you’re pregnant based on the information provided.
My cycle started June 18th I have 27 days cycles, on cycle day 17 I started light bleeding lasted 3 days. My normal period was due July 15th and now its July 16th and still haven’t gotten it. Should I be worried?
My last period was June 13th 2015 , I missed my period on the 8th of July 2015 but I had sexual intercourse the day I was suppose to start what does this mean I’m already a week late?
Hi. We had sex on the 29th of June; period was due on the 12th of July (5 days late). Do you think I could be pregnant? When should I take a pregnancy test? Many thanks.
You can take a pregnancy test now.
My last period was May 18 – 21, 2015. My period should’ve been within June 15 – 24. It’s July 14, can I check if I’m pregnant? Is this normal?
Yes, now is a good time to take a pregnancy test. This blog will also help you http://womanjunction.com/home-pregnancy-test/.
If you’re not pregnant then you need to determine what would cause your period to be delayed.
My period was May 17-21 and June 15-19 (5 days). My period was due the 13th of July yesterday.I still see nothing. My stomach has been cramping but no spotting today. Yesterday test said negative, should I try again today and does it sounds like pregnancy. I’ve been taking Geritol to help me to conceive.
You can wait a few more days to take another pregnancy test. Try another brand. If it is still negative then it is likely that you did not conceive.
Hi Steffy, my period the past 3 months was as follows: First day of period, 28 April; First day of period, 24 May. I had sex on the 3rd/4th June although my partner pulled out. I used the morning-after pill on the 5th June just as precautionary. Then I menstruated again on the 16 June (first day). Does this mean the morning-after pilll was effective? I am now a day or 2 late with my period for July and the pregnancy test shows positive. When did I conceive?
Additional information is needed to answer your question. How long was your June period? Was it a real period or just spotting. Did you have sex after your period started on June 16th?
Ok this is my 2nd post don’t know if my first one was posted…. So i have irregular periods well most of the times…I usually have my menstrual for 5 days. The first day of my menstrual was June 21,2015 and finished on June 24th. On the 25th at about 2am I had unprotected sex and I bled a little and nothing after that. I also had unprotected sex on June 29th and once again on July 8th. Can I be pregnant???
Yes there is a chance you could be pregnant. But with the dates you could provide, I do know there is a possibility. I would recommend you take a pregnancy test within the next week.
Brandie,
OK so I got my period on 7/16th very light and light until Sunday the 19th I bled heavy for a few hours and then my period was done. Is that normal? And I haven’t token a pregnancy test. Not sure if I need to. Just wanted to mentioned when I found out I was pregnant of my youngest I was already 3 months pregnant and had my period once more after I found out.
Hi Steffy.. i had unprotected on 20th march.. From march to june, i had my period respectively.. But this month something weird happened.. On 9th and 10th my i had only light and like few period but only 11th morning it came normal and end on 13th.. Normally my period last for 5 days but earlier when i got my period for the first time it lasted for 7 days.. Plz help me im extremely worried.. Why like this..??
Hello. I menstruated on the 2nd to 5th of July 2015. I had sex on the 5th and 6th of July. Help me, when will I ovulate? Usually my cycle is between 25-28 days. Thanks.
The days that you ovulate will vary because you have an irregular cycle. If you have a 25 days cycle then you will ovulate on July 11 to 15, 2015. On the other hand if you have a 28 days cycle then you will ovulate on July 14 to 18.
Hi Steffy… I had unprotected on 20th March.. From March to June, I had my period respectively.. But this month something weird happened.. On 9th and 10th my I had only light and like few period but only 11th morning it came normal and end on 13th.. Normally my period last for 5 days but earlier when I got my period for the first time it lasted for 7 days.. Plz help me I’m extremely worried.. Why is it like this..??
Hello Sania. It seems you’re having irregular cycles. This post can provide some insight http://womanjunction.com/irregular-menstrual-cycle-occurs/
My last period was from June 16-23. I had unprotected sex with my boyfriend on July 5th twice but he “pulled out.” My period was supposed to start yesterday but nothing has happened. Should I be worried? How long should I wait until I should be really worried? It normally comes 1-2 days late? My breasts normally get tender but they havent.
I had my menses on 02nd May and I had it on 7th June. What happened?
This post will help you to put things into perspective.
http://womanjunction.com/menstrual-cycles-month/