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 period last october 15, 2015 which lasted for four days. Then i take my pills on the 20th but today i got my menstruation again?! Is it normal?!
Hello, Many women experience this its quite normal as long as you’re not feeling pain other than the normal menstrual cramps.
Hi I haved my menstruation on September 21 and my cycle is 28days and on 19 October I haved light pink period and it only last just 1 hour and I feel sick and fever and now 2 days now i have brown inside me only,,, please coud it be pregnancy ,,???????????? I am hoping
Hi my period ended 4th Sept and had sex on the 8th with someone. On the 16 Sept I had sex with another person. All unprotected. I am now pregnant who am I pregnant for pls???
It depends on whether you were fertile on or around the date that you had sex with these men. It is important to know the number of days in your menstrual cycle and whether you have regular or irregular periods. This information is needed to provide you with the most accurate response.
Hi. I wanna ask if I’m pregnant. I had unprotected sex Oct 18 and my menstruation is Sept 26… I expected my menstration on Oct 24 but until now it’s not here.
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.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.
Hello Olly, You can try the following to help you calculate your period…Check your body temperature,Track your vaginal discharge/mucus {Fertile discharge is clear and thin, and it has the consistency of egg whites. You have this kind of discharge when you are ovulating},Test your hormone levels by using an ovulation test kit.
I had unprotected sex with my partner in May 31st 2015 that day I was ovulating, then saw my period on June 14th-17th, had unprotected sex on June 26th with a friend, now I am 18weeks pregnant! Is the baby for my partner or my friend?
When did you have your May period and how many days do you have in your menstrual cycle? This information is needed to provide an accurate response.
My may period was on may 18th to 21st and my period, it’s usually 4 days long but the 4th day is very light, just spots and sometimes my period is 24 days apart i.e from the last day of my last period till the first day of my next period! I hope this helps
My last period was September 25-28 I haven’t had a period since could I be pregnant? When should I test to find out if I am pregnant? Please help.
Your chances of being pregnant depend on whether you were fertile on or around the date that you had sex. 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
please i had one shot of depo-provera in july. i had ma menses on 14 September and my cycle is 28 days. I didn’t go for the next shot in October 9. i had sex on de 8 and took postnor 2 on the 9 october. i had a drop of blood on the 18 and had sex again on the 19. I’ve taken 4 pregnancy tests and they were all negative since october 8 till now. please what may be wrong with me because I am feeling sick. pains in my leg and fever
My last period was 8th October 2015 but had sex on the 17th of October 2015. My cycle is 28 days. Can I get pregnant?
You were most fertile from October 20 to 24, 2015. It is possible, but the chances would be low.
Hello,
I have been trying to get pregnant. I have three children. I took my IUD out on July 13th. My period started that next day and it was a normal menstrual. The following months my menstrual changed to come on the 1st or 2nd of the month and last 5-7 days. When trying to calculate my ovulation dates I found they occurred between the 11th- 19th of the month. However, today is the 25th and my ovulation test strips state I’m ovulating now. Can you ovulate twice in one month? And before your period?
yes, it’s possible to ovulate twice in one month. please read this article for more info
Hi. I had my period on the 3rd of September and was suppose to have my period on the 1st of October but they came on the 3rd of October. I took a pregnancy test came it was negative but I’m having changes as if I’m pregnant. Am I pregnant?
You many not be pregnant. Your period was late by 2 days – this is normal. A woman’s menstrual cycle can change for various reasons throughout her lifetime.
Please my menstrual cycle is 27 days and my menstruation started on October 18 my problem is that I want to know when I’m ovulating.
You will ovulate from October 29 to November 02, 2015. You can also refer to our ovulation calculator via this link http://womanjunction.com/ Simply enter the first day of your last menstrual period and the usual number of days in your cycle then press “Calculate” – the calculator will do the rest.
Hi. I had sex a day before my period (10 October) and had period on the same day (a day before) it lasted only 3 days instead of 5. Now my breasts are sore and I am having pain in my bladder. could I be pregnant?
Hello, If you are feeling pain in your bladder or lower abdomen that should be checked out by a doctor. This could be a sign of lots of things so see your doctor he will run some tests and tell you if you are pregnant.
MY PREVIOUS MENSTRUATION WAS AUG 13 AND IT CAME FOR 15 DAYS WHICH WAS SEP 28, AND ANOTHER ONE STILL CAME 2 DAY, PLS HOW SHOULD I CALCULATE MY OVULATION
Hi I was just confuse because if I had my menstruation last August 26 to 30 and I had my period September 21 to 24 and I had unprotected sex October 12 and until now October 23 I don’t have yet my menstruation. Can you please help me? Am I pregnant?
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.
Hi my last period was September 21 and was supposed pose to come on 19 October I only have period of one day and I was pink it only last just 1 hour. Does that mean I’m pregnant?
Not necessarily. You can take a pregnancy test by October 26 just to be sure. Bear in mind that your period could be delayed for other reasons as well.