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 the 27th of march and I had sex on the 6th to 11th.because I was ovulating that period of time .but surprisingly I saw my period today which is April 23. What can I do please?
Hello, although the chances of pregnancy increase a lot while ovulating, the chances are never 100%. What I can suggest is, that make sure to calculate the fertile period accurately. Try to have intercourse on all of the days of your fertile window. You can also try using an ovulation kit. In case it still doesn’t work, consult a professional and have checkups done to know what exactly is the problem. All the best!
I started my last period on 23 of March and I ought to have seen April’s period the 20th according to the calculator but I’ve not seen it.
You can get the most accurate result if take a pregnancy test by April 30. 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.
Last day of my periods was on 1st this month. had sex from 14th to 17th could i be pregnant?
Hello..I had my period on the 10th – 13th of this month,and i started seeing it again on the 22nd of the month. Though I had sex with my boyfriend on the 16th and took pills..what could be the problem?
Hi Rachel, the pills may cause an early period at times, it is not uncommon.
Hi, I wrote here on april 20th i believe… And i just can’t stop thinking that i don’t want to get my period this month It should fall on the 24th which is two more days and I and my husband have been trying. I feel that i put to much thought into it.
Hi Tanya, did you get your period this week? I hope not.
@emily yes i did get on the 24th-28th and then yesterday i was spotting so maybe this month it’ll happen hopefully
Oh, okay Tanya. Yes, all the best then!
Hey, I have a question. Can anybody answer my question please? I got off my cycle on the 8th of April and I had sex on the 12 of April. Is it a possibility that I might be pregnant, I have been feeling weird since than been having the throw up feeling but nothing come up just gagging.
Hi Annette, there is a small possibility yeah. ATB!
I had my menstruation at March 22 ended in March 28. My boyfriend and I had outercourse at March 31. I know this is my safe days. We were grinding naked about 5 minutes, I think. I was really wet, I dont think pre cum was present. He didn’t masturbated the day before it happpened and he peed before we had outercourse. He said he wasnt even close to ejaculation, he didnt ejaculated near my vagina but he ejaculated on my boobs and I showered the day after, cause Im scared that it might go down to my vagina. But I have read several articles that it can’t get me pregnant. I am on a regular 28 day cycle, Im supposed to get my period on April 19 but it didnt come. Im 4 days delayed. Am i pregnant? But, I literally don’t feel anything. Im super stressed that I think I might get pregnant. Please answer. Thankyou.
Hi Kathryn, you probably have got your period by now. But just for the future, no days are safe as such. Yes, the probability of conceiving is low just after your period and just before your period, but the chances are never zero. So use protection to avoid that small chance.
Hi… I normally have 28days cycle but last two months, it has been irregular. Am supposed to see my menstruation on the 30th of March, instead I saw it on the 3rd of April. I had unprotected sex on the 20th _23rd of this April, please is there any likelihood that I will be pregnant?
Hi Blossom, yes there is a chance of pregnancy as it must be close to your ovulation period. ATB!
Hi Steffy I had my last period on March 25th for 6 days. I’m a regular 28 days cycle…Had unprotected sex with my husband almost every day. Expecting my period today but nothing yet. I took a pregnancy test 2 days ago but it was negative. Could I be pregnant or not?
You were fertile from April 06 to 10, 2016. If you had sex on those days then he chances of being pregnant would be high. Wait a few more days to see if your period will come.
I want to be pregnant but my hubby does not want me what do I do
Leave him and fine someone better to have a baby with.
Listen to your hubby and stay quiet
Hi, I’m usually on a 29 days cycle. However, my last menses came in the 14th Mar and it lasted for 2 weeks till the 29th Mar. This is my first time having my period for so many days as usually it will only last about 6 days. My period have not come for the month. May I know when I should be expecting my next period? Thank you!
Hi Vivi, please see a professional. Don’t get alarmed, but menses for 2 weeks is not normal.
Hi. My last menstruation was February 29, 2016. Usually, my mens lasts for 5 days. It’s already April 22 but still, I haven’t have my menstruation yet. Aside from taking pregnancy test, what are the other factors I could consider in determining if I am pregnant?
Hi V, Other signs are sore breasts, Increased need to go washroom, mood swings, tiredness etc. But these all may be due to other reasons also. The only accurate way to know is to take a pregnancy test. Also, take it after 10 days of missing your expected period date for more accuracy. ATB!
I saw my period on 7th of April it stop on 10th of April and I had sex on 16th of April am I free?
In my opinion the 16th is the 9th day of your cycle, depending on how regular your cycle is or how many days, assuming your cycle is 28 days the fertile period is 14th to 16th day. Since you had sex on the 9th day it’s safe. however the sperm, depending on its health, can stay stay alive for 2 to 4 days and if it stays alive till the ovulation period fertilization can still happen but it’s a small chance. a PT can help eliminate the doubt.
Hi my name is Courtney and last Sunday which was April 18th me and my fiancee had unprotected sex. Last month my period started the 24th and ended the 26th. We are not ttc at this point in our lives. Since the 18th I have been feeling very queasy and light headed my nipples are hurting and sometimes tingle I keep cramping very bad but no period. My period due date is two days away but something is not right. When I eat or smells certain things I get sick to my stomach. Now I know I’m not crazy but I need help so please if anyone else has experienced this help me!!!!
If I had sex on the 17 or 18 and my ovulation dates was 20 through 24, can I still be pregnant?
Yes. The risk of getting pregnant is high because your partner’s sperm can live inside your body for at least 72 hours. You can become pregnant just before ovulation as long as one sperm is alive; in essence the sperm could be there waiting for an egg to be released during the ovulation process.
Hello. My last period date was the 15th of January and I had unprotected sex on February 9 and 10. I’m pregnant. How do I calculate my conception date?