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 got my period on December 31, 2015 and ended on January 5, 2016. I had been having intercourse. On the 13 of January through the 16 I had been feeling my uterus is sore I’m also bleeding could it be my period? Or why does my uterus feel sore and it hurts?
It could be your period. When is your January period due?
On January 26…I also would like to know why I can’t get pregnant; I have moré than 8 months trying, I’m not taking any control pills and I have íntercourse every other day.
I had my period on Dec 18, 2015 and it lasted my normal time. I have had unprotected sex every day almost since then with my fiancee. I was supposed to come on my period today Jan 15, 2016, no period, no symptoms of a period, slight – very slight cramping yesterday. Could I be pregnant or when should I test?
You can get the most accurate result if you wait at least one week after missing your period before you take a pregnancy test. It is even more accurate if it is done first in the morning as the urine is far more concentrated at this time.
Hi, I have a 28 days cycle, I menstruated on 21st December & now on the 13th January instead of the January. Please, I need your professional advice.
I had my first baby in January 2014, and I became pregnant again in May, 2015 but I had miscarriage in my 3months in August 2015, reasons for the miscarriage according to Dr, he said I have O negative blood type and was given antiD injection that was why I miscarried the pregnancy, but he administered Drogam injection to me after evacuation. My challenge now is that I been be able to conceive since September last year I have been trying to. Now I saw my meses on the 2nd of January. What do I do ro conceive again. I need your professional advice.
Hi . I have a 28-day cycle and my last menstrual date was 15th December. I had unprotected sex with my husband from 26-1st January. Per my application I’m supposed to menstruate on 14th January but I bled for 3 days from 11-13th January. It’s the 15th and I’m not seeing blood again. Can I be pregnant? I have severe tummy aches.
Hi,If what you actually saw the 11-13th was your period then you are not pregnant but if the blood you saw was not like a normal period it could mean you are pregnant wait another week and take a pregnancy test to find out.
I had my last period on 14 Dec and still not had one. Had sex on 25 Dec when OPK was positive but HPT has been negative to date. Had sore boobs for last 4 days but not today. What do you think?
Hi my last period was December 2nd and I haven’t had one since then. What do I do? I don’t know when I ovulate because my periods are irregular and it is the 14 of January. I’m so confused.
I strongly believe you might be pregnant because my last period was Dec 5th I took a HPT Jan 6th and it was positive I also have irregular periods.
My last period was the 6th of December and lasted for 4 days. On the 21 of December, I was bleeding again just for that day and I had sex and now I’m unsure of when I’m supposed to get my period. And why did I bleed for another day when I already had my period?
Bleeding between periods can happen for different reasons. Read more here http://womanjunction.com/spotting-between-periods/
I haven’t had sex in 3 years now but I have missed my period for 3 month could anything be wrong?
Yes, you need to visit you doctor for an assessment.
My last menses started on 29th November and ended on 6th December. I had sex on 3rd January and my menstruation is not back. Can it be possible that I’m pregnant?
Your chances of being pregnant depend on whether you were fertile on or around the date that you had sex. Can you confirm the number of days in your menstrual cycle? This information is needed to provide you with the most accurate response.
I had my last period in November around thanksgiving more like Nov 24 – 31 and haven’t seen my period again. I took a pregnancy test, it said negative now it’s Jan 14 and still no period… WHATS GOING ON?????? PLS HELP.
You can have missed periods without being pregnant. Read our blog post for more information http://womanjunction.com/8-mess-period/
I had protected sex on July 6th but I don’t know if the condom broke. My cycle came on July 15th thru 19th…I had sex around that time…I am now pregnant 26 weeks as of today January 13, 2016 and my due date is April 20th 2016. My doctor said I conceived on the 25th of July. Is it possible that having sex on the 6th got me pregnant?
No, it is not possible that you got pregnant on July 6th. Your doctor is correct, you’re 26 weeks pregnant.
I had my last period. on 12-16_15. ,I had unprotected sex on 12-24-15. I experienced mid cycle bleeding on 1-2-16 tbat lasted for four days. My scheduled AF has not came. Could I be pregnant?
my last period is december 15 my husband and i had sex december 19 and 22 do i will get pregnant untill now I’m waiting for my menstruation
hello im lisa i was just curious as for when i concieved ………period is irregular very so as i can remember oct 17 i got it then for nov it did not come until dec 4 i had sex the 16th 19th 21st 23rd and the 24th did not get my period for jan i tested on the 6th it was positive 1-2 weeks which date was i likely to concieve please and thank you
Hello, It would be hard to tell the exact time you conceived but you can get the closest possible date which would be the 19th and 21st day hope this helps.
My period are always regular, and always 28-29 days apart. Lasting 4 days…
My last 3 periods were:
10/15/15
11/13/15
12/11/15
January is a no show. It was supposed to come 01/9/16
Me and my husband did have unprotected sex for about one week and a half… I should’ve tracked when I was fertile, we had sex on all my fertile days.
I have been feeling some symptoms now that you look back and think about it more.
My last period was on December 14 and I had sex on Jan 10. Can there be a chance of me getting pregnant?
Your chances of being pregnant depend on whether you were fertile on or around the date that you had sex. Can you confirm the number of days in your menstrual cycle? This information is needed to provide you with the most accurate response.