Menstrual cycle     Ovulation kits     Ovulation signs     Pregnancy


Using a Menstrual Cycle Calculator

Please select the first day of your last menstrual period:

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Usual number of days in your cycle:

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 that you are at your most fertile, and thus stand a greater chance of a sperm reaching the egg and fertilizing it. One of the biggest problems people have however is knowing how to calculate their menstrual cycle. This is where technology can come in useful. You can use items such as a menstrual cycle calculator which should provide you with a rough estimate about when you are next going to ovulate. Let me tell you a little about how these 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. These types of cycle calculators often give the most accurate results, but many people find that they are ‘over kill’, and the majority of the information that they ask for is not something that people will have to hand readily, especially months of data about the subject. Therefore many women use simpler menstrual cycle calculators, which still give fairly accurate results.

The first thing that the menstrual cycle calculator will ask you is the date of your last period. Hopefully this should be information that almost any woman should be able to answer fairly easily. This will be the starting date of the last period and not the ending date.

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, and others it could be as low as 25. However, you are only after an average here. Do try to be as accurate as possible though as this will affect the results that you are given, and this of course will have a profound effect on what the calculator tells you is the ideal time to try for a child.

Finally you will be given your results. Generally you will be told the date of your next period, which should be fairly accurate. What you are going to be most concerned with however is the next ovulation period. This will be the time that you are at your most fertile and therefore stand the best chance of getting pregnant. What you do need to remember though is that the information isn’t 100% accurate as it is impossible to predict the human body, so ideally you would want to start having sex a couple of days before this, and a couple of days after.

Whilst they aren’t 100% accurate, the menstrual calculator is still a useful tool. It provides a ‘free’ way of knowing when you stand the best chance of getting pregnant, and this of course can be a god send for a couple who are struggling with this.

Learn more about Menstrual Cycle and how to to calculate it manually.

311 Responses to “”

  1. Elsa says:

    hi everyone, brief history: I had my Mirena IUD removed on SEPT 25th 2014 after 4 years. I didn’t have an actual period until NOV 22nd normal 6 days for me. Im due to have my period on DEC 20. I haven’t had any symptoms or sign of my period is coming, just been really sleepy, stomach doing flips when i eat certain things. I had unprotected sex with my fiancé (my sons father) and he came inside of me everytime even during my FERTILE WINDOW. Could i be pregnant?! We want to conceive our baby #2 already! Any Advice?

    • Tianna says:

      Wow I’m in the same boat as you, I also had my last period on nov.22 which was my bday. Lol but my period was really strange it just would come and go like one day it was flowing and then nothing at all the next day. I always have my period for 7 days and last month it lasted on and off spotting for 9 days. Right now I have being feeling really moody,tired & sore breast. I’m not sure what’s going to happen but I’m going to get a home pregnancy test.

  2. Amara says:

    I saw my period on 3 December by 10pm, and had sex with my hubby on 14 and 15 December, am I pregnant. Reply

  3. Novi says:

    Hi. I had unprotected sex while on my period. Although I know the risks and consequences, how late can my next period be? As of now, I am one day late. How long should I wait before taking a pregnancy test?

  4. ann says:

    i had my menses on 19th November and had sex on 6th December can i get pregnant

  5. WorriedGloria says:

    My last period was 12th Nov but expected period today nothing yet. Could I be pregnant …

  6. sheen says:

    hi my period come the 18 of November and i have sex the 27 and the 28 and my partner came inside of me. i wonder if I’m pregnant

    • Clepetark says:

      Hi , having unprotected sex is not a guarantee to get pregnant, but having sex during your fertile window with no protection indeed increase the chances of it.

      test yourself if your next period delays !

      Good luck

  7. Rosa says:

    thanks i will go see my doctor

  8. tyra says:

    I had my period on October the 19
    And on November the 20th I had my next period
    will that make my menstrual cycle 32 days if so when is the best time to try concive

  9. fatimah says:

    I had my last period in October 6 and the date often reduce by two days interval and this month of November started on 7 .when should I be expecting my ovulation seeking for baby for the past 7 years of marriage.

    • Clepetark says:

      I don’t understand really what is your question, but conceiving for irregular cycle is pretty easy, track down your fertile window as followed : the day 1 of your cycle is the day one of your period. day 7 to 12 is your most fertile days. Have intercourse one day on 2 from day 9 to day 12 as it will allow more mature spermatozoids to be released and increase your chance of success

      Good luck.

  10. DaniGirl says:

    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????

    • Clepetark says:

      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

  11. nancy says: period came on 12th November and I want to know when I will be ovulating

    • heather says:

      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

  12. Rosa says:

    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?

    • Clepetark says:


      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

  13. BabySyndra says:

    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

    • Deana says:

      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.

  14. Celestine says:

    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?

    • Clepetark says:

      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

  15. Celestine says:

    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

  16. pretty says:

    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

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