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 started on the 14th of December and I had unprotected intercourse on the 19th of December. Is there a possibility I could be pregnant? My shortest cycle is 28 days, longest 29 days. Thanks.
If your periods are regular, you were fertile on December 26 to 30, 2016. You were not ovulating on December 19, so you’re not pregnant.
Hello I started my period on 11/27/2015. It lasted for 5 days. I did not have a cycle at all in December. Then 01/01/2016 at 5:45pm it started. It lasted for four days but not heavy. Can I be pregnant? Additionally, I’ve been feeling cramping periodically in the lower abdomen but felt no cramping during cycle.
My period started on the 6th of January and stopped on the 9th. When will I ovulate? Thanks.
With a regular 28 to 30 days cycle, ovulation typically occurs on the 13th – 16th day. The ovulation signs include changes in body temperature, cervical mucus and hormone levels. Pain in the ovaries may also be experienced.
Hi. I have my period on 21 December, my next period is on the 15 January but I am sick, sore and heavy breast, little pains under my stomach, watering mouth and a cold. Could I be pregnant? We have been trying to get pregnant for 2 years.
It is possible that you’re experiencing PMS. Wait to see if you’ll miss your period. Take a pregnancy test at least one week after if you miss your period.
My last period came December 5, 2015 until December 8, 2015. Supposed to had my period on December 28, 2015 I’m nine days late. Moody with lower stomach cramps from 30 to 45 seconds. Do you think I should take a pregnancy test or wait on my period.
Yes, you can take the pregnancy test now.
Hi Steffy, I had my last period on 15/12/2015. After that, I have been having unprotected sex with my boyfriend from 24 until 31 December. I did a PT (results were negative) on January/04 this year, I’m to do another one in 2 weeks time. I haven’t seen my period this month. Lately, there has been vaginal cramping and backache pains radiating to the waist, nausea and vomiting, tiredness, constipation and swollen breasts. Should I be worried that much or am I just overreacting?
When is your period due? The symptoms may or may not be due to PMS or a pregnancy; the symptoms are similar at times. You need to ensure that you’re testing at the right time as well. 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. If you have tested at the right time and you’re not pregnant then you need to have your symptoms assessed by your doctor.
Ok, so my last period was Dec. 22nd and I was on the pill til Jan. 3rd which was when my hubby and I did the Baby Dance. I haven’t taken my pills since then and today, Jan. 7th, I’m spotting. My next menstrual cycle isn’t until the 19th. Any thoughts?
Since you just came off the pill, you may not conceive that quickly. Keep trying to conceive; give it some time. Good luck!
Hey, I had my period on November 27th n then no period for December as of right now I’m 13 days late. Could I be pregnant?
My last period came on the 10th of December and finished the 15 and me and my bf had unprotected sex from that until the 26. My next period was expected to come on the 7th of January. Am I pregnant?
Hi . I have my period on the 22 of November and had unprotected sex and it’s January 7 and I have not seen my period since. Is it too early for me to do a pregnancy test?
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 thing in the morning as the urine is far more concentrated at this time.
This is the time to do it; HPT in the a.m for accurate results!
I saw my period on 10 Dec and I had a lot of unprotected sex with my husband and today is 7 January. I was supposed to see my period but no sign of them. Do you think I might be pregnant?
The most accurate way to confirm if you’re pregnant is to take a pregnancy test 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.
Hey, I started my period on the 8th of December 2015. It is now January 7th 2016 I’m cramping little like I’m on it but no blood yet! Should I be worried?
No, you should not be. Since this is your second period it may take some time for it to have a set routine.
Hi, my boyfriend and I are trying to conceive but haven’t had any luck in doing so. We regularly have unprotected sex around ovulation time as well as when I’m not ovulating. My cycle is 24-25 days. From my last period on the 11th of December I have been feeling kinda off, light cramping every few days, sinus migraines two days in a row, back pain, hungry but then a little nauseous but I never throw up. I also have experienced light-handedness and feeling tired.I expected my period on the 6th of January 2016 and it came, but it seems kinda lighter than normal. It is only thin strip of blood on the pad. I have not tested lately for pregnancy and starting to lose hope that I will actually get pregnant. I had a miscarriage about five years ago as well. Can you help me?
Please read our How to get Pregnant Guide for more information http://womanjunction.com/how-to-get-pregnant-guide/ Good luck!
I had abortion on 5th October 2015 & bleeding came till 12th November 2015. Then my periods starts from 6th December 2015 & ends on 10th December 2015. Before my abortion, my cycles were 30 days regular. I had unprotected sex with my husband on 16th, 18th, 20 & 22nd day from my LMP date. Today is my 33 days period not come & also I suffered motion problem last one week, frequent urine. Today, I take home pregnancy test, its comes negative. Please help me.
It is normal for your cycle to adjust after an abortion. It may take some time for it to be regularised. Read more here http://womanjunction.com/?s=menstrual+cycle+after+abortion
I had my period on 30 November to 5th December, had unprotected sex on 27th December 2015 now I haven’t had my period. Am I pregnant?
Your chances of being pregnant depend on whether you were fertile on or around the date that you had sex. The number of days in your menstrual cycle is also needed in order to respond accurately.
My last period was on the 18th of december 2015,I had sex on the 21th, 25th and 28th of december. please am I supposed to be pregnant because my cycle is usually 25 days or 27 days long. Thank you
Hi, Once you have unprotected sex you stand a chance to get pregnant,try taking a pregnancy test.