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 my last period on march 17 had sex march 27- 28-30 April 1 . had spotting on April 9 . can I be pregnant ?
there’s a possibility that you are because I had sex around the same days that you had sex and I noticed that my nipples get a little bit bigger. I’ve had my last period on March 17 so I would say this about 2 more weeks to test if you should have a positive, but test in the morning
Had my last period march 12, unprotected sex but the day I’m most worried about is march 27th. Could I be pregnant??
hi my last period was Jan 31 2015 – its now April 12 & I still have not gotten my period yet … I have took multiple of home pregnancy tests & its still showing up negative – what am I to do ? any suggestions ?
I can only suggest you to hurry up and visit your gynecologist. When I say to hurry- I mean today. There are multiple reasons why you don’t have your period and the pregnancy is only one of them. The reason maybe hormonal, health related, related to the medications… You name it. The most important thing is to make that visit and see for yourself why your period is late for 2 months.
My last period is March 7, 2015 then I had a sex with my Bf last March 30, 2015 but until I don’t have a period… Could there be a chance of being a preggy? Thanks!
I had my period last month on March 10 an I supposed to get my period April 7th now I have a period on April 11, what does this means when I’m a few days late. I wanted another child but unfortunately I had a period
pls can i get pregnant the first day of my period
No darling if you are bleeding you can’t get pregnant. You can only get pregnant while you are in the fertile period and you can calculate that period with the calculator above.
Hi I got my last cycle march 14 to the 20 and it was on for 7 days and it said my next cycle will be April 11 which is today i been having sex with my husband since the 21 of march if my cycle don’t start when should I start testing
You should start testing within 2 weeks
Hello. My last Lmp is March 14 2015 I had sex with my bf last March 29. He released inside me. After we had sex March 30 up to apr 2 my breast are paining, I took pt yesterday and it shows negative. Is there’s a possibility that in pregnant? Until now my nipples are sensitive.. Thanks in advance
The sensitivity can be subjective but it is the fact that you had a successful intercourse with your boyfriend in your fertile window. I can only advise you to visit a gynecologist and determine if you are pregnant or not. The pregnancy tests usually show negative during the early stages of the pregnancy.
First day of my last period was March 11. Had sex about four times since then. Yesterday I had mild cramping, leg aches, and I was spotting a pinkish color. Could I be pregnant??
It doesn’t matter how many times you had sex during the month, but when and how. Your description equal menstruation, so I suggest that you don’t worry so much. If you are planning a baby then calculate your fertile days and if you are not, try practicing safe sex.
if i had my period last march 11 2015 and had sex last march 27-31 and had spotting april 6 and 7, am i pregnant?
Of course u could…anytime you have UNPROTECTED sex there’s a chance for pregnancy….if u haven’t gotten a period then u need to take a test…
Mom to 2!
The first day of my last period was March 7,2015. I had sex on March 28, 2015. My period was supposed to start April 4, 2015… Can I be pregnant?
You had sex at 21st day of your cycle and it is uncommon to get pregnant so late. From what you are saying I can only conclude that you can’t be pregnant.
Had my period march 17 ,2015 I do not recall how long I have it for. I had sex 16 March 2015 , and 25 and April 4 , am I safe , just had a baby 2 months ago , I do not want to get pregnant now
The women who just had babies are at the best to get pregnant again, very fast and very simple in the fact.
Specially if the 45 days elapsed and you are not breastfeeding so your hormones are speeding again.
You couldn’t get pregnant at 16th, but you can all those dates after.
Practice safe intercourse with your partner if you don’t want another baby.
The fact that you had one recently just adds to the possibility of another pregnancy.
Hi
I had my period on the 23rd of march. Had sex 30th of march @nite then had sex 31st of march midnight. Can I be pregnant
You should calculate your fertile days by the pregnancy calculator and your better judgement.
If you are not planning baby, play safe.
If you have a normal ovulation, the 30/31st March is way too soon to get pregnant, roughly saying.
I had my last period on the 17th March 2015. the issue is that, I don’t know when my ovulation comes because I don’t feel pain and my cycle last within 3 days am not sure if my cycle is between 26 to 28 days.can I get a quick reply please?
The irregular periods are common to the younger women and to the women who suffer issues with the ovaries, like the recurrent ovarian cysts or even the inflammation of the bladder that transfers to the ovaries.
You don’t need to feel any pain during your ovulation. You might have slightly elevated hormones, more discharge or slightly elevated body temperature.
The best is to take 26 days for your reference point, the lower limit, as you say that your period lasts only 3 days, so it is possible that you have a short cycle.
I have endometriosis. I had a regular cycle in Nov 2014, December 2014 and January 2015; no cycle in February 2015 and on March 13th I had a very light cycle that was off by March 14th. Since then, I’ve had itchy breasts that now feel full; cramping, dull back pain on the right side, frequent urination, bloating some nausea and dizziness. I took a home pregnancy test this morning but it was negative…. could I be pregnant.
The nature of your distress indicates that your fertility is severely degraded. You should take regular checks and specially if you are trying to have a baby make sure that you visit the doctor. It is very hard to say anything and in your case trying to get pregnant can pose much greater danger than in a person who has no health issues. The described symptoms are all common for the women of the similar health background.
I had my period last month February 26th but I didn’t get it in March and it is now April the last time I had sex was December 3rd