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





Hello, the first day of my period was on 12/8/2014. It ended on 12/14/2014. I had sex on Dec,19,2014. Started spotting on 12/26/2014 but left the next day. Today is 1/1/2015 and been spotting since last night 12/31/2014. Could I be pregnant?? P calculate shows expected next period would be on 1/5/2015
Wait and see if your period comes if it doesn’t you may be pregnant …take a test or two
Hi I started my period on 11/12/15 and my boyfriend came home on 11/26/15 so we had sex like 3 days after i started spotting but it stopped my next period was to start on 12/6/15 but it didn’t come it’s now 12/8/15 and I started spotting last night but when I woke up nothing was on the pad I really don’t know what’s going on cause when I have sex I bleed but nothing be on my pad can you tell me if I’m pregnant on my period will come down
Hello, There are many reasons why you could be spotting for example: Ovulation: Some women notice light spotting for a day or two after ovulation. This happens regularly for some people.
Contraception: Spotting between periods is a common side effect of hormonal birth control, like birth control pills, hormonal IUDS and patches, shots and implants.
Pregnancy: Many women experience spotting during pregnancy. It usually happens in the first few months. This can be harmless in a healthy pregnancy. Try taking a pregnancy test.
Hi , with the roller coasters of the holidays, getting up early, getting to bed late, stopped the gym for some .. drinking a bit, meeting with people, it is more then enough to mess up the more regular cycle, You are early on schedule to be pregnant but life is always finding its way. Test yourself as soon your period delays
Good luck
Hi I was wondering I came on sep13th had sex on the 17th then again round the 26th when did I get pregnant? Is it possible I got pregnant on the 17th I know it says I ovulate from 25th til 29th but its important to know it I could’ve got pregnant on the 17th ??
hi, it is possible but hard to say without the length of your cycle .. we are now in December and you speak about a September period … you have none since then? and just start to wonder what is going on , or it is a typo mistake ?
Good luck
Hello again well when I came on sep13 I went off on the 16th then back on on the 18th after having sex on the 17th so my period wasn’t normal so yes I’m very confused
Hey. Had sex Dec 3 2014. Waiting for my period to come around and it was due on the 21st
I have a question, my LMP was November 26th-30th , I’ve had unprotected sex with my husband on a few occasions throughout this month of December yet haven’t gotten my period this month yet ???when should I test or what should I do?
Hi ,
the best moment to test yourself is when your next period will delay, test yourself with the first in the morning urine, if you use a pee on a stick test, as this urine is containing the highest concentration of HCG, the hormone the test is looking for.
Good luck
Hi I had my period in nov 11-19 and I have not gotten my period yet and it’s Christmas, I did a preg test and its negative. Could I still be pregnant?
I have a question, my LMP was December 27th-30th, when is the right time for me to have sex and get pregnant.
My period is always on time every28 days but my period was due on jan 2 and ive taken 2 pg tests that both say negative could I be pregnant?
Hey I had sex on December 2 2014 an I’m waiting for my period to come an it was supposed to be here on the 23 uggh I’m nervous can I be pregnant….
My last period was 18th November 2014 and the next should come by 16th December but I haven’t seen my period now, then I had unprotected sex with my partner on November 30th, what could have happened
Hi , you were into your fertile window when you had unprotected sex, you might be pregnant. Test yourself.
Good luck !
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 fiancĂ© (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?
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.
Good luck if you are trying for a baby that’s what happens to me with my son so do a test best wishes
I saw my period on 3 December by 10pm, and had sex with my hubby on 14 and 15 December, am I pregnant. Reply
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?
Hi , as soon you are one day late you can test yourself, use the first in the morning urine, the HCG concentration is greater so the result will be more accurate.
Good luck
i had my menses on 19th November and had sex on 6th December can i get pregnant
My last period was 12th Nov but expected period today nothing yet. Could I be pregnant …
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
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
I have my period on the 18 of October. My period lasted for five days. I want to get pregnant so bad I’m 34 years old when should I start having sex after my period.
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. However, you will start ovulating around the 11th day if you have periods 25 days apart. Alternatively, you will not ovulate until the 20th day if your cycles are longer, like for 34 days. If periods are irregular it would be more challenging to determine the fertile days.
thanks i will go see my doctor
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
Hi ,
The first day of your period is the day 1 of your cycle. Your fertile window is day 10 to 17 of it.
Good luck !
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 date.am seeking for baby for the past 7 years of marriage.
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.