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 had Mirena removed November 3rd. My cycle came November 7th and lasted 7 days which is normal. I had my cycle December 6th and ended the 8th. I had another cycle December 30th and ended January 1st. I haven’t had a cycle for January yet unless the second cycle was my cycle for January. Could I be pregnant?
I had my last period December 13th lasting six days. Being unprotected everyday after that using the withdrawl method, which is not a good strategy, I know. I have irregular cycles and my period has not come yet. Im not sure if I should take a pregnancy test, I am scared…
Go ahead and test now. Good luck!
Hi. the first day of my last period was on the 14th of Dec. and the last day was on the 17th. I had unprotected sex on the 18, 22, 25, 27, and the 31st. I have a 32 day cycle and I was supposed to get my period on the 15th of January and I have this feeling in my lower abdomen it feels like it’s something poking…but I have no pregnancy symptoms at all.
my boyfriend and I were having sex and the condom broke. Lately, I have been having back pains..it is the lowest part of my back by my butt. I also have pain in my left side and the bottom of my stomach. what is going on? My period came on Dec 26. I have about 33 or 34 day cycle.
I had my period on the 16th Dec 2016, not had my period of January 2016, in November I had my period on the 10th, and December the date changed, will I get my period on the 22nd of January, because I counted from Nov to Dec 37 days?
My period came on December 8th went off December 12th I have a 32 day cycle when do I ovulate? Me and my husband are trying to get pregnant but don’t know when to have sex when I’m fertile the most
Hello,Your next most fertile period would have been December 24, 2015 to December 28, 2015.
If your cycles are 32 days long, you ovulate on day 18.
My last menses started on 2nd January and ended on 5th January 2016. I have a 29-day cycle, I’ve been having unprotected sex with my boyfriend from 15th Jan up until my fertilization last. We both want a baby. How soon can I take a pregnancy test?
Hello,Wait at least 2 more weeks i know the wait is horrible but you want to get accurate result good luck 🙂
My last period was December 12 I had unprotected sex December 27, am 10 days late for my period am I pregnant?
My period reduce from five days to three days and doesn’t flow as usual though is still very regular but have been trying to conceive for 8 months. my question is can that affect me getting pregnant?
Hi, No i don’t think that affects your fertility lots of women experience longer or shorter periods sometimes,all you need to do is calculate you ovulation days properly so you don’t miss having sex before you ovulate.
I had my mirena taken out on the 24 of December, had sex that same day …then had my period again for 1 day on the 6 of January now is the 18 of January and i feel cramps and nausea …i would like to know when is my next period coming or am i pregnant???
Hi,If what you experienced on the 6th of January was actually your period and not some other kind of bleeding associated with pregnancy like…implantation bleeding.then you might not be pregnant the only thing you can do now is wait and take a pregnancy test to find out.
hi my last month periods was 25th December, now 18th Jan again. it comes too early…in last month after my period continuously till jan 8th we had intercourse. don’t know what’s happening in my body. often i get too early periods …this all is happening only after marriage …some physician said I have bilateral small cysts in my ovaries. is that a reason for my delaying pregnancy?
pls I had my menses from 29th december to 1st january. I calculated with the menstrual calculator and my ovulation was from the 10-14 January 2016. please does it mean 18 january is a safe day for me? tnx
the chance of conception is lower if the calculation is correct, but you should still use some form of contraception if you don’t want to get pregnant
Hi I just gave birth 3months ago and had my first menstrual period on December 17,2015. My husband and I make love January 1st,2016 and it was withdrawal method. It’s already January 18 and still I have no period. I am confused in counting my cycle what is suppose my next menstrual period my period ended December 25,2015. Is it possible I am pregnant again? Thank you and God bless you
Hello,Since it was unprotected sex and the withdrawal method doesn’t work sometimes it is possible you are pregnant,all you can do now is wait and take a pregnancy test.
My period was on 4th of this month but I didn’t get it. On the 9th of this month, I had sex where I was wearing a panties but still I am scared of being pregnant. I took a pregnancy test after 2 days and it showed negative. I took after a week like on 17th Jan and it was negative but I am not getting periods. Why?
You missed your January period but had unprotected sex in that month as well so testing in January may not give you the most accurate results. Your period may be late for other reasons but wait to see if your February period will come. If it doesn’t come then take the test one week after that February date.
I saw my period on 25 December 2015, had unprotected sex on January 4,5,7,8 2016. Now I am feeling sick. could it be that I am 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.
Has your boob started swelling a little bit yet
Yes
My last period was the 12th of Dec. I took a test yesterday it was negative. I have an irregular cycle and my period lasted 7 days. I have had unprotected sex on Dec 30. I’m fatigued, dizzy, have huge boobs, back pain, frequently urinating and I’m always wet below thinking it’s my period but it’s not diarrhea. Nausea you name it…I already have five kids and I don’t know what’s wrong with me, could I be pregnant?
The best way t confirm is to ensure that you take the test at the right time. If you miss your January period, then take a pregnancy test at least one week after that date.
Ok then that’ll be the 19… let’s see what happens. Thank you.
Still nothing 36 days since last period. Now I’m going to the rest room every hour can’t control bladder. 3 negative test and I got clear liquid coming from boobs. Im l mean my boobs are huge and nipples,very sensitive…. what now I’m still lost