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 need advise!! Okay so I was recently off the pill for a few weeks. I had my last period start Oct 21st but was off & on flow wise until Nov 4th. I figured this was because I missed the pill for so long. After going to the Dr she gave me a new pill that I started the new pill November 12th. My boyfriend and I had unprotected sex on Nov 8th. These calculators say I should have started my period around the 22nd of Nov. And I still have not. Should I be worried? Idk if Im being paranoid or what but this past 2 weeks I have been extremely tired, bloated to where my stomach would hurt, light headed, and have a crazy sense of smell these days. Any Advise????
Hi , if you conceive before starting the pill, it will not abort you … take a test as soon you are late for your next cycle. Also it is recommended to use a physical protection for 14 days after you started the pill to make sure it had the time to take its full effect, which your pharmacist should had made you aware of.
Good luck
Hi..my period came on 12th November and I want to know when I will be ovulating
Hey Nancy did you get your period? My last period was November 12th and I have a 25-26 day cycle and haven’t started yet. I’ve been having egg white cm seems likes since ovulation
hello my last period was October 2th while i was 21 days late the next day nov 25 i wiped and saw very light pink blood also watery it lasted 4 days my periods usually last 7 days and im regular on the 1st of December i did a home pregnancy test did it in the afternoon it came out negative . should i do a blood work test or just retest again in the morning?
Hi,
i dont know what you call being regular but being 21 days late on a previous cycle, having a 4 days light bleeding one and a 7 days normal periods then finally being 4 days late on the last one . This is far from being normal. Having such changes in your cycle I can deduct tht you are not on birth control pill as , on them you would be set like a clock and would not worry about being pregnant. These pee on a stick test are always more effective on the morning urine as it is the one the most concentrated in HCG, the pregnancy hormone, but being 4 days late, the morning or evening doe snot matter anymore as the HCG level is increasing everyday and more you are late easier is to tilt a positive test, is there is pregnancy going, I think your result is accurate. For your erratic cycle you should mention it to your physician, if you are wondering the cause. New life style, stress, new gym routine, diet .. all affecting the cycle too
Good luck
thanks
I’m 39 yrs old and been w/ my other half for 11 years. My lmp was on Oct 17th to Oct 24th. Periods are always regular and never had been late before. I don’t know how many days cycle that would be, if anyone can figure it out? Someone told me 32, but dunno. Anyways, I was 11 days late yesterday and had some pink/brownish blood on pad then wiped and was light pink. Today it was watery and red sometimes bright red & was kinda clear mucus like stretching too when I wiped. So taking its my period late, maybe? I had intercourse on the 11/8th. Really want to have my 1st child and figure out how many days my cycle is if the 32 is correct. Any help is appreciated and thanks in advance
Normally ovulation occurs around 14 days after the start of your cycle. You actually can conceive if you have intercourse before ovulation and one day after. To figure out your cycle days count from the first day of your period, to the start of the next.
Hi. In october I was delayed and my period came on November 2 until 14. I had unprotected sex with my boyfriend last November 21. Am I fertile? Is there a possibility that I am pregnant?
Hi , yes depending if the lengh of your cycle it is quite possible that you had your unprotected sex into your fertile window.
Good luck
Hi. On october i was delayed and my period came on November 2 and I had unprotected sex with my boyfriend last november 21. Am I fertile? There is a possibility that I might pregnant? Please help Im really confuse. Thankyouu
Hi I had my last period on November 3 and am supposed to have my next period on December 1…I had unprotected sex with my partner on the 22 November so is there any chance that am pregnant
I had sex on September 30,2014 that night my menstrual cycle came on . Then it went off october 7,2014 since then I was mild cramping very light head spotting twice light pink light brown wanted to vomit clear discharges still haven’t had a cycle for October and November. I took a hpt test that afternoon and it was negative Could I be pregnant and retry and take the test in morning ????
Hi,
try the test with your first morning urine when your periods are due and late. You will have a clear answer
Good luck
Lately i have had a increase in white milky discharge with no odor.. Along with that i have had headaches,abdomen cramps and tender breast. I ovulated 12-16 of November…i had unprotected sex before,after and during this time. My period is week away. Could these be mc or could i be pregnant?? I took a pregnancy test which came out negative 2 days ago. Please help me. We have been trying to conceive for 7 mths now.
Hi, so I got my last period on the 30th of October. I had sex on the 13th of November in which the condom broke inside of me. Now I’ve been experiencing cramps and wonder in they could be implantation cramps or menstrual cramps. Besides waiting for the outcome, is there any way I could figure out which it is sooner? Plus I have back pains now, but not lower back pains but a tad higher. And my mouth get watery like I have to vomit but I never do. Is this just a mind thing or could this be early signs of pregnancy?
Hi,
what action did you took knowing that the condom broke at the time, did you took an emergency birth control pill withing the 72h of the incident ? If not well, you have effectively pregnancy symptoms, but be careful, the stress of thinking that you might be pregnant also trigger you these symptom and you are listening much more to your body that you normally do…. as soon you are late test yourself with a pee on a stick test with your first in the morning urine. You will then know what would be next !
Good luck
Please could you reply to this
Hi,my last period started on 27th October 2014 ,which lasted for four day.it is today ,25th November 14,what shall I draw from this,?
If you have your period that you have a 28 days cycle if not that you have a longer cycle … your question is very incomplete …
Hi I had a period on the 26th of October and I have it on the same day of every month and I am later on my period by 3 days now. I knew I ovulated as had pain. I also got thrush 4 days ago and just wondering if I could be pregnant or not. I never miss any of period as I am normal regular,I have been having cramps in my belly thinking I was coming on my period and when I didn’t it was a shock.
Please reply
Hi I’m so confused I had my period on the 16th of October till the 22nd. I had unprotected sex on the 19th while on my periods,is it possible that I’m pregnant for I’m late by 6day already,I stopped breastfeeding my 24months old in september just wondering if this could have an impact in my circulation.
Hi, yes there is a chance for getting pregnant even if you have unprotected sex while having your period especially if you just stop breastfeeding your hormones will set you slowly on your new cycle.
Good luck
hello i got my period on October 2/14 and i was suppose to get my period on November 2 and i still haven’t gotten my period im 17 days late ive been cramping on and off lighted headed and discharge an stomach been hurting i haven’t taken a hpt yet. do you think that i can be pregnant and what advice can yall give me.
Hi, well my dear you are not a curious one ! with 17 delays and these symptoms rush to do a test !
Good luck
Your pregnant…. When I got pregnant the first time those where the symptoms to the t. Take a test ASAP!
Hi my period came on 19 Nov and I want to know when I will be ovulating.
Pls I had my last period 20 October but I had sex 26 October and have not seen it this month. Is it possible am that am pregnant ? And the problem I have is that I don’t know how to calculate my ovulation period thanks.
Hi , the regular fertility window is between day 10 and 17 of your cycle, day 1 being the first day of your period, hope it will help
God luck