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





Hey so i had my period last week of September it lasted 4 days i had unprotected sex October 15th an just found out i was pregnant October 29th is it possible to find out this early?? Or is it that i could be pregnant by someone else
Hi, Some pregnancy tests can detect pregnancy 6 days before your next period is due.
Hi I have been trying to get pregnant ever since April 14 which was the day I had my Implanon removed, it is now October 29, 2015. I have a really bad case of irregular period. My first period was August 17,2015 then the next one i had was October 7th that lasted 7 days been having Sex a few days after it was finished. Of course I’m trying to conceive and have been feeling random pain in my breast. How does ovulating works after your period. Could I be pregnant.
Hi,Ovulation usually occurs between 12 and 14 days before your period starts this is an average, so it could be a couple of days earlier or later.Your egg survives no more than 24 hours after you’ve ovulated However, sperm can survive for up to seven days. which means that you don’t have to time sex to the exact moment you ovulate to get pregnant. You actually have a fertile window of about six days. Breast tenderness is a sign of pregnancy but it could also be a sign of PMS.
I’ve been use so many birth control,but they don’t work well in my body, so I want to control by calendar,exp if I had my period October 20 but the last day is in October 24 what is the best day for me to have sex without no birth control.
there are other options besides pills also available like condoms, cervical cap, diaphragm, IUD…please consult your gynecologist for the best option
How do I calculate my next menstrual cycle?
The menstrual cycle starts on day one of the bleeding to day one of the next. On average, the cycle lasts for 28 days, but it’s normal to have it longer or shorter. So if one period started on July 10 and the next one started on August 5, then you would have a 26 days cycle. If your periods are regular, then the two subsequent ones would come on August 31 and September 26. Read this article for more information.
Hi. I had unprotected sex Oct 9 but my last menstrual was Sept 30 and I had my menstrual again Oct 27 to 28 and it lasted for 2 days only – supposed to last 4 days. What happened? Do you think I’m pregnant?
Hello. Your chances of being pregnant depend on whether you were fertile on or around the date that you had sex. Also, a shortened period, “The menstrual period and cycle are generally affected by lifestyle practices and the surroundings. Stress from relationships or work can cause you to bleed more severe or to stop much quicker than normal. Increased exercise can help to shorten your menstruation cycle.” Read more at this link http://womanjunction.com/differences-long-short-menstrual-cycle/
Hello, my period was on the 8th of Oct had sex on the 17th now on the 27-28 had a brown discharge and cramps now it’s all gone. Could I be pregnant? Hopefully.
Your chances of being pregnant depend on whether you were fertile on or around the date that you had sex. It is important to know the number of days in your menstrual cycle.This information is needed to provide you with the most accurate response.
I’m 31 & my husband & I just started trying to conceive. But I’m confused on how many days of my cycle & therefore I don’t know when I ovulate. August 28 or 29 2015 I had a regular period. I didn’t have a period in September. Oct 5th my cycle came on. I used a ovulation tracker but I’m unsure of when I ovulate because of how my period has been doing lately. Can you help as to how many days are in my cycle?!?!
Hi, From the information you have given me the length of your cycle is 37 days.
Hi. If you conceived on September 29 then you would be 6 weeks pregnant. Pregnancy symptoms can be experienced at this time.
Hi first day of my last period was on d 4th september I hv a 28 day circle on d 13 I had sex with my bf and on d 19 I was ovulatig on d 20 I was fertile n 16 same so now I’m pregnant I would like to know d exactly date I concieved my bby n on d 18 my bf came
Hello..
My period came 19-10 instead of 17-10 and last for four days. I have breast tender during my period and after, my nipples increased, my breast fuller n bigger sometimes I feel cramp. I usually feel cold in the morning, My urge for sex increased. This has never happened to me before. I did home pregnancy test very early in the morning yesterday but negative.. What the cause of this symptoms. plz I need help, your reply is important.
My monthly period come on 1of October and come back again on 25 of October. Is it normal or there’s a problem.
It is normal to have two periods in a month. Please read this link for further details http://womanjunction.com/menstrual-cycles-month/
I saw my menstruation on the first and I finish on the 5th and I had sex on the 6th.I have been having sex on my ovulation dates but nothing happened. I expect myself being pregnant but I didn’t. Hope I’m ok?
You must ensure that you’re computing your fertile days correctly. Typically, the menstrual cycle will last for 28 days, which is calculated from day one of a menstrual period to day one of the next cycle. Ovulation typically occurs 14 days before the start of your menstrual period. If your cycle lasts for 28 days, you can ovulate on the 14th day like the average female. Read more at this link http://womanjunction.com/fertile/
Hi please today 27 October I just lost a pregnancy ???????????? please when will I be lucky again?
Hi. So sorry to hear. Your chances of getting pregnant again depend on your body. Your period should return within 4 to six weeks and it is possible to get pregnant again after this first period. Ensure that you’re mentally and physically ready. Good luck!
My previous period started 19th of September, my menstrual cycle is 29-30 days. Me and my partner had sex 5th of Oct just once and none since then. I’m expecting that I’ll have my period 19th of October, but I don’t have it still. I started feeling hot, my breast were tender on the 11th of Oct up until yesterday. On the 21st of October, I had witnessed and brought my friend to the hospital as she had an accident. Until now I don’t have my period. On the same day I checked my pads and found blood and so I thought my period came however it stopped.until now. I’m still experiencing cramps, however this time I don’t feel hot anymore and my breast are no longer sore. Please help me. Am I pregnant?
You were ovulating at that time so it’s highly likely that you conceived. 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. The urine-based home pregnancy tests offer great accuracy. T
Hi,
I got my first day of periods on 15th October and completed on 21st October. I had sex on 25th October. I had took a medicine for an infection under the guidance of the doctor. I am feeling nausea, vomiting and feeling sick since last two days. Is it possible that I m pregnant?
Maybe not. It could be that you’re experiencing side effects from the medication that you’re taking. Consult the doctor that prescribed them.
I had a baby through C-section August 8th and he was Still birth,and now I have had my second period which was October 13th – 17th exactly 5days and my husband and I made love on the 18th (Sunday) and 24th (Saturday ) today the 27th went to wee and wiped and saw brown discharge like period is about to start feeling like period is coming but it is not red blood could I be pregnant again just 2months after my last delivery and operation and when is the best time time to check plus my period is not due till 10th of November
Hello,This time-out gives your body a chance to heal and recover from surgery. Research shows that getting pregnant less than six months after a c-section can increase your risk of complications like a ruptured uterus or having a low birth weight baby during your next pregnancy. It also possible you are pregnant.
Thanks Kelly after the 27th when I had the brownish discharge nothing came again but yesterday started feeling period is coming so I would wait till the 10th when my period is meant to start to see what happens