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





My last period was February 22nd me and my boyfriend had sex on March 11th and 12th my period is supposed to be here today and it hasn’t came yet he did finish in me both days I have frequent urination non stop and slightly sore breast and really tired could I be pregnant or do u think my period will come later ?
Per calculations it is said that you have a short period ( barely 24 days, right) so your fertile days should be somewhere earlier than a date you listed above.
For you the most fertile period was March 02 to March 06, 2015.
hello , i had my last 2/18. my average cycle is 26 days. on 3/15 I had light spotting , then got a little more heavy , but was on different spots on the sanitary wipe. Today It looks like its my last day of my menstrual & it has only been 72 hours .. Will it be too early to take preg test ?
I hope you can help me , Thankss
It sounds like a possible pregnancy, and yes it would be too soon for a commercial test but not too soon for the official visit to your gynecologist who can confirm pregnancy from the day one.
I had my period January 2,2015 then January 30,2015 it is now March 17,2015 and NO PERIOD 5 NEGATIVE HPTS I Have had my period since I was 12 and never missed other than having my daughter what could this be
You should have gotten your period more than 2 weeks ago, so yes this could be something else. If your test is negative, it might be too soon to test yourself or you are having some other types of issues.
As you have already and probably tried a few types of tests I urge you to see your family physician.
Hi, my last period was on Feb 11. today is March 16, I took the test yesterday and said I wasn’t pregnant, should I take the test again within a few days?
Chemical tests are accurate and reliable only after a certain time, if you don’t use any pharmacological preparations, pills or other prescribed chemicals. The polycystic ovaries usually cause the instances of a prolong menstrual cycles, or vice versa.
If you are planning a child, wait a few days, if not or if you usually have this occurences please visit your gynecologist or make some blood tests.
My last period was February 16. Since then I have been having unprotected sex with my husband. The first week after my period when I had unprotected sex I took a plan b pill and a second pill again in five days. I had unprotected sex now with no plan b pills since the end of February. I have been extremely nauseous, headache, stomach cramps, extremely emotional, and hungry way more than normal. I’ve taken 4 clear blue pregnancy test and all say negative. But I’m also unsure of my period because I took 2 plan b pills in one month, also if my symptoms can be related to plan b ? Please help!!! I’m extremely stressed. Tyia
Hi, plan B is an emergency birth control system. Why did you take it twice in the same month. If you don’t want to conceive it is your responsibility to take the proper birth control method. Plan B is completelly changing your cycle by force trigger periods to avoid a possible conceive egg to attach in the endometrial tissue. Taking it twice, I am not surprised that you are not feeling right. Test yourself only when your periods are late. If it is still negative, please consult your physician to discuss contraceptive options .
Good luck
Hi the last menstrual I had was February 12,2015 my menstrual only last about 5 days.. And now its March 10th and I still don’t see it…should I panic? Or just wait to see if it’ll come today?
You should get your menstruation on March 12th, if you still have no news, please consult your gynecologist.
Hello, Lmbo was 2/8/15 I was due 3/9/15 I’m three days late I believe I had sex with my husband between my fertile times not sure, I haven’t been pregnant in 12 years this would be awesome for my husband and in which we have no children together but I worry so much I’ve been extremely tired and low dull back pains and abdominal cramps similar to a period just not as intense ok I’m hoping you guys can help thanks…….
Hi, I think it is time for you to test yourself ! that will be the only way you will know if you have a little angel on the way or not. Skipping a cycle is also normal due to many factors such new gym routine, new job or any kind of stress.
Good luck
My last period was Jan 22 15, my period was supposed to come Feb 19 and now we are at march no period and had a negative test
There are many other reasons besides pregnancy that can make your menstruation skip the term, so to say. One of the reasons are hormones and age. You forgot to mention how old are you and the usual length of your period.
My period was on 25th February 2015. I had sex on 11th of March. I am worried whether I will become pregnant. My period are normally 30 days. Kindly advice
if your last period was on 25th that means your fertile window is between March 8th and March 12th. so yes, there’s a high risk of pregnancy. I hope you took a morning after pill, if you don’t want a child. good luck and please be more careful next time
Here’s my problem: I have hypothyroidism and recently got my RX right about six weeks ago. I also had a tubal ligation during my last csection 10 months ago. I am currently late on getting my period, and have started lactating again. In addition I have several more pregnancy symptoms, but last night got a negative result on a pregnancy test (not surprising since I got a tubal). Just wondering if anyone has had anything similar and can help me figure out what’s going on. I’m going to wait three days and take another test just in case I’m one of the 1%, and then get an apt with my doc. Thanks.
-Confused
hi, your completely right, after tubel only a tiny fraction will conceive by accident. With hormonal therapy, you can trigger pregnancy symptoms. If your next test is still negative, give a call to your pharmacist to verify with him the possible side effect of your medication.
That will indicate you if you need to see your doctor quick or if you can wait for next routine appointment.
Good luck
Hi my period came on Feb. 14 2015 and lasted five days. and it was supposed to come on march 14 but it didn’t. It is two days late . the test came negative.
hello pls help i had my period on the 8 of feb and had sex with my husband on the 22,23 n 24th of feb. respectively my next period is expected on 10th of this march but till now it hasn’t come though since the 22nd i have been having this stomach pain. am i pregnant? or what?
Hi,
I am not sure if I pinpoint your need here, do you have a reason to believe that you might be pregnant ? Did you protect yourself or let the nature goes ? Being pregnant is no causing stomach pain, until you get nauseous, your stomach is not involved whatsoever in early pregnancy symptoms. Test yourself, it is the best way to answer to your question.
Good luck
i’ve been having the same thing
Hi…so I had sex February 10th menstrual came February 12 was on until February 16th-17th….but now it’s March 10th…should I be worried?
I saw my last period on the 18th February 2015 that lasted for 4 .
I had sex with my hubby on the 5 and 6 of March .Today the 7 of March ,my period started again .I’m afraid right now, is it normal to see my period 17 days after the last one ?
Pls help a sister out .
Thanks .
Hi,
changes in the cycle are possible but uncommon, did you star a new gym routine, a new job or being stressed for any other reason ? Did you quit taking birth control pill lately ? All these possibilities need to be looked at as possible causes. If you keep having a 17 days cycle it might require from you to have an appointment with your physician for more assistance, in order to track your ovulation properly.
Good luck
I need to know why this is happening
Hello. My cycle started on feb. 3 It lasted only two days. My boyfriend and i had sex before my ovulation date and after. I was due for my period to come on March 3 but it haven’t yet. Could it be possible that i may be pregnant.
Yes, you could be pregnant as you obviously had sex with your boyfriend at the top of your fertile period and also after, so it covers prolong period.
If you know when you are having your ovulation, in theory you could be in an early stadium of the pregnancy right now.
In order to be certain, please consult your doctor
I saw my period on 30th Jan and I slept with my husband on 13th Feb ,today is 5th March I haven’t see my period again am I pregnant or not ? I done urine last on 3rd march the result shows positive. What is the cause of the delayed period or should I go to ultra sound scan .
Hi, i am not sure if I follow you but, if you had a positive test, unless you take a medication that can trigger a false positive, well you are pregnant. If you are unsure about your situation please visit your physician, he will arrange you a blood screening. You will have your final answer ! Periods can also be delayed due so many factors such as stress, new gym routine, moving …
good luck