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





Hi. My last period was July 19 and my periods come pretty regularly and last for 6 days. I had sex on the 1st of August and my period is supposed to come this weekend. However, the last free days (like 3-4 days) I’ve been feeling somewhat nauseous on and off all day and it kinda goes away with putting something in my stomach. And the last 2 days I’ve been going pee more often. Is it possible to be pregnant? If so would it be to early to test?
Hi Lily, It is possible to be pregnant,you can test 2-3 days before your missed period preferably in the morning when you wake up.
hi i had my last period on july 11 and period lasted for days but its august now and i was suppose to get on august 8th but it didnt come now im 5 days late and i took a hpt but it was negative
Hi my last period was july 10 and i had sex during my ovulation and still waiting for my period so could i be pregnant and pregnant test it says not pregnant
My cycle suppose to came on on the 11 I had sex on my ovulation day an my last cycle was on the 14 of July some body please tell me
My menstruation for the month of July started on the 12/7/15 and this August it has started on the same day. Pls I which to know my unsafe period for this month. I wish to be pregnant. Thanks
Hi Brigitte, Your next most fertile period is August 19, 2015 to August 23, 2015.
I had sex on the 8th of Aug 15 and my boyfriend sperm came inside of me and I didn’t start my cycle yet. And we did it again on the 10th of Aug 15 and I started bleeding on the 11th and 12th of Aug 15 is it possible I’m pregnant?
Hi Jennifer, it’s unlikely that bleeding would be due to a new pregnancy because implantation bleeding takes about 7-10 days to manifest. If the spotting wasn’t because of your period or ovulation (which can cause light spotting in some women) and it does persist then you should see your doctor about it if you’re concerned, but spotting can happen for lots of reasons like hormone imbalance and cervical irritation so I wouldn’t be too worried about it for now. If your period is late then I would suggest taking a pregnancy test.
No, you’re not pregnant.
Hi I had sex one into my ovulation is there a chance I could be pregnant Im am due to start my period on the 14 of this month I am just now starting to have symptoms but the could be period symptoms
Hi Denise, what symptoms are you having? it is possible to be pregnant, take a test when it’s closer to your period or visit your doctor.
Thank you…. I been having the nauseating feeling For awhile but now Im starting to get head ache and my breast are tender to touch
I’m going through the same thing.Except I’m supposed to start my cycle today & i woke up feeling nauseated .Me and my husband have been trying to conceive for. 3mths now so hopefully this is it!!
Had protected sex on the 20th of July and my period came on the 31st. Been feeling nauseated and bloated lately. Is there possibility of pregnancy?
I had last sex on June 10. I got my periods on July 8th. But Aug till date I didn’t have my periods. . Will I be pregnant. . Please reply
My period came 4th July and lasted 3 days. Afterward,I had protected sex on the 20th of the same month. My next period came on the 31st of July and it lasted 4 days. But I’m feeling very queasy,bloated and lightheaded. Could I be pregnant even if my normal period came after having sex with a condom?
that would be very very unlikely!
I had sex on 26 July and 29 july was my ovulation period can I get pregnant?? I want to know please help me please…. I’m waiting for the answer thank you
yes! if you didn’t protect yourself then there’s a risk that you might conceive
After I got my period on the 4th of July(which ended on the 6th),I had protected sex on the 20th of the same month. My next period came on the 31st of July and it lasted 4 days. Now I feel bloated and nauseous. Could I be pregnant?
Hi Noella, have you taken a pregnancy test? if you have any doubts that you could be pregnant you should take a test or visit your doctor.
No,I haven’t taken a test. Maybe I’m just being paranoid. But when is the best time to take a test? My next period is supposed to come on 28 August
I started my period on 11 august 2015 and I finished on 13 of august 2015,when will it be good for me to get pregnant.
Hi. I am 13 weeks prego today and i want to try to figure out when I conceived. On April 11th i had my period, then again on May 11th.. making at a 30 day cycle. I had sex with someone on on May 14th and then had sex with my ex boyfriend on May 22nd and up. I found out i was prego June 14th and they could not tell me how far along I was at the time do to it only being the yolk sac and machine couldn’t measure it.. now that I am further along im just very curious.
Hello KathyCarr, its hard to tell the exact day you were conceived,your most fertile days were may 25 2015 to may 29 2015 but congrats and good luck 🙂 .
My period in june was on the 11 and my period in july was the 10 i was looking for my period 8/8 or 8/9 no sign except cramps but slight today breast are aching slightly took a pregnancy 8/8 was negative what could be the issue
Hi Nicole, Did you have unprotected sex between july 22 to july 26? if so u can be pregnant. take a pregnancy test
I need help I had my last period july 11th and came off on the 15th and had unprotected sex on the 17th he came in me every-time.. & have been having unprotected sex every since then.. its now August 10 and I have not had my period can I be pregnant?
HI Tarsha Jones, Of course you can be pregnant you have been having unprotected sex! take a pregnancy test or visit your doctor.
Hello, my cycle began on the 21st of July & I downloaded a few apps for menstrual cycle/Ovulation calendar, I ovulated Aug 1 until Aug 5. I made love to my 5yr fiance’ on the 2nd,3rd & the 6th! Is there a chance for us becoming parents?
Hello Deja, your most fertile days would be august 2 2o15 to august 6 2015 so it is possible for you to become parents! 🙂