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. My last period was on 12-16-15 and I was supposed to get my next period Jan 7 th but no period. I took a pregnancy test yesterday and the line showed up very light. Could I be pregnant?
If you have two lines and you’re pregnant it doesn’t matter if one line is lighter than the other.
I had sex September 6th and got my period afterward and I had it Oct, Nov but not December. Does this mean anything or am I good? No pregnancy symptoms at all and I am very active, I do competitive cheer.
It is possible that you’re not pregnant. Your period may be late due to other reasons including exercising. Read more here http://womanjunction.com/8-mess-period/
Thanks
I got my period on the 9th to 13th of December and I had sex on the 18 of which I took the morning after pill. I haven’t had my period to date could I be pregnant?
The morning after pill is known to delay period. To be absolutely sure you can take a pregnancy test. You can get the most accurate result if you wait at least one week after missing your period. In addition, the result might be even more accurate if the test is done first in the morning as the urine is far more concentrated at this time.
HI Cece, Just wanted tp share my experience. The morning after pill failed me twice. So it will not work if fertilization has taken place already. Your best bet is to take a test. Best Wishes!
my last period Dec 13, had sex January 09. do I have a chance of pregnancy? I don’t know my fertile days
Hi, Yes you still have a chance to become pregnant.
Posting for my oldest daughter…last period was 11/16/2015. Missed December period (she just realized) took at home pregnancy test and it was negative. When should I have her retest??
Hello, Wait couple more days and then test again preferably in the morning first pee when you wakes up.
My last period was on 13-Dec-2015 & had sex on 9-jan-2016. what is the chance of pregnancy? Should I be worried?
My last period was Dec 12. It’s now January 11. My husband and I had sex between December 24 and Dec 31. Should I wait until January 20 to test?
You can get the most accurate result if you wait at least one week after missing your period. In addition, the result might be even more accurate if the test is done first in the morning as the urine is far more concentrated at this time.
I came on my period Dec 10th 2015. It’s Jan 11th 2016, I took a home pregnancy test and went to the emergency room today and they did blood to see and it was negative. I’ve never missed a period. And every time this happened I was pregnant. Was I testing too early? Me and my husband want another baby.
The best time to get the most accurate result is if you wait at least one week after missing your period. Note also that there are different factors that can lead to a missed period – read more here http://womanjunction.com/missed-menstrual-cycle/
I had unprotected sex on the 4th and 10th of January and my last period started on Dec 28 lasted 4 to 5days. What are the chances of being pregnant?
Hi,Once you have unprotected sex the chances are very high for you to become pregnant.
Hi…I had my period on the 11th of December and on the 19th we had unprotected sex with my husband so I was expecting my period on the 8th of January but it came early on the 4th and it lasted 4 days after 2 days I had a white discharge and now I’m spotting I’m not really sure what is happening…is it possible to be pregnancy we really want to have a baby we got married last year April…please help
Hi,Breakthrough bleeding or spotting is quite normal and nothing to worry about, but if you saw your period it’s quite unlikely you would be pregnant unless it wasn’t your period but some other type of bleeding associated with pregnancy.you can still take a pregnancy test to be sure.
My period came on the fifteenth of December and lasted 6-7 days it is now January 1. When should my period come on again? I’ve also been sleepy and eating more, and in December it came on early than normal.
I had my period Dec 10, 2015 and I had my paraguard removed Dec 30 2015. It is now January 11, can I be pregnant?
I had a still birth August 8 2015 he was 8 months old baby. had my period 3 times after that and it was normal, missed my period for a month and thought I was pregnant. did a test blood and urine but it came back negative. period comes 24th of December 2015 and lasted 7 days to be precise till 30th of December. I had sex with my partner 1st and 2nd of January 2016 and then also on the 7th of January and period starts on the 10th of January and it is not due to be here, I am meant to be ovulating. please someone help my menstrual cycle has gone bunkers now I don’t know when I am ovulating or when period is due. I am totally clueless is this what they call hormonal inbalance and how can I correct it so I can take in again. 38 this Apri,l I hope I can get pregnant again
Hi,The best way to solve hormonal imbalance is to have a talk with your doctor he will know what to prescribe for you to get everything back on track.what you are experiencing though is quite normal sometimes your body goes back to normal but sometimes you need medications to help you talk to your doctor.
hi my last period Dec 28-30, had sex January 09. do I have a chance of pregnancy? I don’t know my fertile days
Hello, Yes it is possible you are pregnant as you can get pregnant anytime after unprotected sex.
Hi. I turned 50 last year always had my cycle never miss. I have only been late three times in life that I am aware of. My last period was Dec. 4, 2015 today is January 10, 2016 and I haven’t had my period. So I bought, to be honest, a $1 home pregnant test today and took it but it only showed one line. What does that mean for me? The test was 99% accurate.
You must read the instructions and ensure that you understand how to read the results. Each manufacturer will determine if they will present the results with one or two lines; it depends on the brand. Re-read the instructions and be guided by them.
In most test it’s 2 lines for it to be a positive test. But as mentioned reread the instructions. If you’ve missed your period and you’re not pregnant you could be going through menopause. Every women is different and goes through menopause in different ages and differently. I am no Dr. or RN i suggest you make an appointment with your Dr for further advice.
I had my last period on Nov 30th 2015 and it ended on 4th Dec 2015, I had unprotected sex on Dec 11th and used pills on the 12th. I had sex on the 26th of the same month but was protected. I have not seen my period today (Jan 10) but I have done a pregnancy test which tested negative. Should I do another test or what?
You may not be pregnant since each time you used protective measures. Do not do another test right now – wait a bit to see if your period will come. Remember also that the anxiety of the situation may further delay your period.