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 period happened last may 21-27 few days from that day I had an unprotected sex with my husband until 5th of the month of June but I am not sure if I was fertile by that time cause my monthly period has different days to wait before my next period. How will I know if I am fertile or not / if I will get pregnant?
Hi Jovy, If you have irregular periods you could use fertility charting, basal temperature tracking, and purchased ovulation test kits to predict ovulation. For further info on these, read http://womanjunction.com/body-basal-temperature-predict-ovulation/ and http://womanjunction.com/category/ovulation-kits/
My period is regular. I miss my period yesterday and today so I took the chance to have the pregnancy test but it turns out to be negative. So I guess I am a bit early for the test. Should I wait for few more days before doing the test again or should I go directly to the ob?
it’s up to you. I would wait few more days before taking another test (so it’s one week from the date your period was due)
My period usually lasts four -five days
It was on May 21 through the 25 was the last and I was fertile on 1st through 6th of June according to apps and online tools
I am now 5 days late and I only had sex once on June 2, during the fertile days.
And I have been having urges to pee but not having to actually pee, the smell of a cheeseburger made me want to throw up and the smell of poop at work (I’m a CNA ) makes me want to vomit.. (Usually it does not bother me I have been doing this for 3 years)
My normal foods I eat I get sick after
I have diarrhea for a few days and then constipation the next few.
Today I was walking into the store and it just took everything in me to get out of car and start walking
I’m afraid to test
When would be a safe time to test?
Hi Amber, you should take a pregnancy test 10 days after your missed period date.
I had an unprotected sex with my husband within the month of may, and my last menstration was on 7th of may , yet to see my messes for the month of june. am so worried because i dont plan for having a baby now, please. Could it be that am pregnant .
Late period can be caused by many reasons. Pregnancy is only one of them. Other reasons may be sudden change of diet or exercise, birth control pills, physical sickness or even mental stress. If you think pregnancy might be the reason in your case, wait until 10 days after the date of your expected date and then take a pregnancy test. This waiting is to ensure the accuracy of pregnancy test kit.
My last period was May 1st 2016 & my me and bf had sex around the 14 and its June 10 and I haven’t gotten my period help please!!
Late period can be because of many reasons. Pregnancy is only one of them. Other reasons may be sudden change of diet or exercise, physical sickness, birth control pills, or even mental stress. If you think pregnancy can be the reason in your case, wait until 10 days after the date of your expected date and take a pregnancy test. This waiting is to ensure the accuracy of pregnancy test kit.
What if I had a sex with my bf on april before my period ended. Then my menstruation came on may, and in june.. I am pregnant for that or not?
Hi Jonnica, there are very rare chances of you getting pregnant if you had sex during your periods. Also, if the periods you had in May and June were normal, most probably you are not pregnant.
I had unprotected sex with my partner on my ovulation period but he didn’t release inside me. Will I get pregnant?
Having unprotected sex is always risky but you may not be pregnant since he did not ejaculate inside you.
Joyce, you can still get pregnant even if he didn’t came inside of you. If he was still in your vagina even if he pulled out you can still get pregnant. It only takes one sperm to get you pregnant and even precum can make a woman pregnant. Your man won’t know if he precums in you or not. so if he says no, don’t believe because it just comes right out. If you think you may have a chance of being pregnant, I would get checked. Ps. I have a friend who got pregnant like that.
I found out I havin hormonal imbalance two days after my peak period,and I’m actually undergoin treatment can I still get pregnant?
Hi Queen, yes you can get pregnant while being on a treatment.
My LMP was sep 24-28th. I had sex on sep 29 but it’s saying I’m fertile Oct 4-8 , I had sex Oct 8th as well, and my due date is June 30th, can it be possible that the sep 29th intercourse could’ve got me pregnant?
Hi Keaira, Sperm can live inside you for 2, 3 and up to 5 days. You could have sex and then actually conceive 4 or 5 days later with your ovulation. So yes pregnancy is sometimes possible
On 23 april 2016 me nd my bf had a little foreplay. This included a little genital contact but not sex. I took ipill on 25 to avoid risk.
My period date for next month was 4 may but came on 5. This month i am already 4 days late.
This is worrying me.
Can anyone help me in finding me out a way?
I’ve been having sex with my husband , it’s June 8 and last time I feel on my period was April 27 till like the 4th or 5th of May. But I keep taking pregnancy test and they keep coming back negative. What could I do to find out if I’m pregnant ?
Hi Vanessa, if your pregnancy test shows negative and you think you are pregnant you should get a test done at your doctor’s or at a medical centre. Also you could try changing your pregnancy test if you are not satisfied.
I had my menses on the 13th of may 2016 and av been having an unprotected sex since than waiting to see me pregnant but it only menses that I saw on the 7th of june instead of 12th or 13th of june2016, what can be the cause?
Hi, Sometimes because of hormonal changes or stress you can have early periods. Are those periods normal? As sometimes it could be implantation bleeding also which is a sign of pregnancy.
Helloy,i was late 3 days on my period, after it ended i had sex 9 days later. i check in here and it shows that i had sex on my 2nd peak ovulation day. could i be pregnant?
Hi , having sex on ovulation gives you the best chance of getting pregnant but not assures it. Take a pregnancy test to check.
Hello. I had unprotected sex one day before my ovulation began, which was 21st May and I had sex on May 20th. I did a pregnancy test one week later which showed negative.. i am expecting my period today but haven’t had it yet. I am freaking out. Can I be pregnant?
Hi, Having sex around or on your ovulation days gives you the best chances of being pregnant. Take a pregnancy test to check if you are pregnant or not.
pls I had sex with my boyfriend on 15th may a day after my menstruation.I had my period on the 10th may n ended on the 14th.my next period is to start from on 4th June but nothing. l had a p.test at first it was negative n the next day l did it again it was positive.my cycle is 25 n sometimes 28,pls I’m confused. am l pregnant because l know l can’t get pregnant a day after menstruation.
Hi, there is rarely any chance of one getting pregnant if having had sex during their periods.However, If your cycle is shorter, for example every 21 to 24 days, this means you are ovulating earlier in the cycle. Sperm can live inside you for 2, 3 and up to 5 days. You could have sex towards the end of your bleeding and then actually conceive 4 or 5 days later with your early ovulation.
Started my period on June 2Nd ended on June 6th had unprotected sex June 5th having bad sharp pains bad headaches for two days peeing alot I know impossible to be pregnant so what’s happening. -.
Hi, there is rarely any chance of one getting pregnant if having had sex during their periods. However, If your cycle is shorter, for example every 21 to 24 days, this means you are ovulating earlier in the cycle. Sperm can live inside you for 2, 3 and up to 5 days. You could have sex towards the end of your bleeding and then actually conceive 4 or 5 days later with your early ovulation.
Also probably it could just be some hormonal changes or stress reason that you could be having any such symptom
Can someone get pregnant while u are seeing ur period ?bcoz I have unprotected sex while seeing my period 3days ago
Hi, there is rarely any chance of one getting pregnant if having had sex during their periods.However, If your cycle is shorter, for example every 21 to 24 days, this means you are ovulating earlier in the cycle. Sperm can live inside you for 2, 3 and up to 5 days. You could have sex towards the end of your bleeding and then actually conceive 4 or 5 days later with your early ovulation.
Pls I’m Emily.l had sex with my boyfriend a day after my menses on 15th may.l have missed my period in June.l had my last period on the 10th may.my cycle is 25days.l had a p.test n was negative n l had the second test it was positive. l don’t understand.am l preqnant??
Hi Emily, try taking a pregnancy test of different brand and which has higher sensitivity level than your current pregnancy test.