Ovulation calculator

Each woman's menstrual cycle is different, so getting to know your body better can improve your chances of conception.

This ovulation calculator allows you to find out when you'll be most fertile, and what your due date would be if you got pregnant on these dates.

Ovulation calculator

What was the first day of your last period?

What is your average cycle length?

Are you ready to conceive? Take our quick quiz to find out.

For the best chance of getting pregnant, you need to maximise the chance of your fertile egg and your partner's sperm getting together. You can only get pregnant on the few days each cycle around ovulation, when an egg is released.

When is the best time to conceive?

To increase your chances of getting pregnant, you need to get your fertile eggs and your partner's sperm together as often as possible. You can only get pregnant on the few days each cycle around ovulation, when an egg is released.

How does the menstrual cycle work?

  • Your cycle starts on the first day of your period and continues up to the first day of your next period.
  • At the same time, eggs begin to mature in the ovary.
  • The lining of the womb thickens ready for fertilisation.
  • During ovulation your cervical mucus becomes thinner and clearer to help the sperm reach the released egg.
  • About 10 to 16 days before the start of your next period, an egg is released from one of the ovaries (ovulation).
  • If sperm is present at the moment of ovulation, or some time during the next 24 hours, the egg may be fertilised.
  • If the egg has not been fertilised, the egg is re-absorbed by the body, the hormone levels drop, and the womb lining is shed. This is the beginning of your next period.

Read more here about how pregnancy works

Conception and sex

To boost your chances of conceiving, aim to have regular sex throughout your cycle so you know that there should hopefully be good-quality sperm waiting for the time that the egg is released. An active sex life is all most people need to conceive.

If you are quite sure when you ovulate each month you can give yourself the best chance of getting pregnant by having sex in the days leading up to ovulation. Continue having sex during ovulation. After this your fertile time will be over for that cycle.

Taking a pregnancy test? Read about how pregnancy tests work.

How to spot the signs of ovulation

Ovulation usually happens about 10 to 16 days before the start of your next period, so  it helps to know your cycle length before you start trying to conceive.

You may never have considered when you might ovulate within your cycle, and if you have been using a hormone contraceptive such as the Pill, you won’t have had a natural menstrual cycle for a while.

As a first step, mark on your ovulation calendar the dates that you bleed during a period. You can then count how many days from the first day of your period to your next period to work out the length of your cycle.

Cervical mucus changes

The cervix secretes mucus throughout the menstrual cycle, starting off sticky white and gradually becoming thinner and clearer.

Before and during ovulation the mucus increases and becomes much thinner, slippery and stretchy. Women often compare it to raw egg white.

This thinner mucus is designed to help the sperm swim easily through it. It indicates that you are in your fertile phase, so this is the time to have sex if you want to get pregnant, but use contraception if you do not!

The last day you notice the wetter secretions is sometimes known as ‘peak day’ and for most women this occurs very close to the time of ovulation.

Temperature

You can also find out about your menstrual cycle by keeping a note of your temperature each morning when you wake up. Your temperature rises by about 0.2°C when ovulation has taken place.

As it is only an indicator that you have ovulated, and doesn’t tell you when your fertile time starts, this is not very useful for most women.

Using ovulation test kits (also known as ovulation predictor kits)

Ovulation predictor kits are available from chemists and are fairly simple to use. They work by detecting a hormone in your urine that increases when ovulation is about to take place.

The simplest ovulation test kits check for luteinising hormone (LH), which surges 24-36 hours before ovulation. This will help to identify the best two days for conception, although a woman can be fertile for a day or so before and after this time.

It is best to become familiar with your usual menstrual cycle to help figure out when you should start testing. If you have an irregular cycle then an ovulation predictor kit can help you identify the time of ovulation, but expect to use more of the test strips.

Sources

  1. Macdonald S, Macgill-Cuerden J (2012) Mayes’ midwifery: a textbook for midwives, 14th edition, London Balliere Tindall

 

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Last reviewed on June 13th, 2017. Next review date June 13th, 2020.

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Comments

  • By Kim pola (not verified) on 5 Dec 2018 - 22:54

    I had my period on OCT. 31 and had protected sex on NOV. 6, i'm not sure to any condom leakage. And up untill now DEC. 6, I am not having menstruation. Am I pregnant?

  • By Midwife @Tommys on 7 Dec 2018 - 16:38

    Hi Kim,
    It is unlikely that you are pregnant if you had protected sex, however the only way to know if you are pregnant is to take a test.
    Best wishes
    Tommy's midwife

  • By Uchechi (not verified) on 5 Dec 2018 - 18:43

    I had my period on 26-29 Oct n have sex on 11th Nov till now I v not see it again

  • By Midwife @Tommys on 7 Dec 2018 - 16:33

    Hi,
    It may be that you are pregnant, I would suggest for you to take pregnancy test to see if you are. In the meantime we would advised for you to be taking a daily folic acid supplement if you think you maybe pregnant.
    Best wishes
    Tommy's midwife

  • By Anonymous (not verified) on 30 Nov 2018 - 05:03

    my period began on 18nov-21,and I had sex on the 29th Nov,what can I use to avoid pregnancy considering that chances are high?

  • By Midwife @Tommys on 3 Dec 2018 - 14:17

    The 'morning after'pill is an option but it does need to be taken within 72 hours of unprotected intercourse. Suggest you see your doctor for advice.

  • By sophie Richardson (not verified) on 26 Nov 2018 - 17:18

    Hi I have just been diagnosed with pcos so I have irregular periods anyway but me and my husband have been trying for about 4 years and had 1 misc and then 1 phantom pregnancy and I have just finished my period after 30 days of bleeding so when would I be fertile thank you xx

  • By Midwife @Tommys on 27 Nov 2018 - 16:53

    Hi, thanks for posting please look at our Digital Pregnancy Tool
    https://www.tommys.org/pregnancy-information/planning-pregnancy/planning-for-pregnancy-tool
    As you have been trying to start your family for 4 years now please go back to your GP and get referred to a specialist for more help.
    Warmest wishes on your journey
    Tommy's Midwives

  • By Trish (not verified) on 24 Nov 2018 - 10:51

    I had my cycle Nov 4-8th my ovulation day was on the 17 but I had sex with my boyfriend on the 16th am I at a good chance of being pregnant? I want to buy a pregnancy test but I don't know if it's too early to do so

  • By Midwife @Tommys on 26 Nov 2018 - 10:58

    Yes, it is too early. Best to wait until your next period is due. Take care

  • By Christabel (not verified) on 22 Nov 2018 - 02:48

    I had my period on the 1-5th of October and I have not seen it till 22nd of November

  • By Midwife @Tommys on 22 Nov 2018 - 11:31

    Hi Christabel, Thank you for your comment.

    If you are having unprotected sex, could there be a chance that you are pregnant? If you are bleeding now and you think that you may be pregnant then we would suggest that you see you Dr to be checked over. It could also be that your periods are irregular but again you will know your body better than anyone. Take Care, Tommy's Midwives x

  • By Ola (not verified) on 14 Nov 2018 - 22:29

    I had my period on Oct 23 and since I finish and not had any sex when can I have sex and pregnant?

  • By Midwife @Tommys on 15 Nov 2018 - 14:01

    Hi Ola, Thank you for your comment.

    It is difficult to know what you are asking. You can have sex at any time but if you are trying to get pregnant then your most fertile time would be around day 14 of your cycle or 14 days after the first day of you last period. If you have not had a period since the 23 October then you next period should be due. You may want to wait until you have a period then start having sex after that to maximise your chances of conception. Hope this helps, Take Care, Tommy's Midwives x

  • By Claud (not verified) on 11 Nov 2018 - 16:01

    I had my period on oct 12 to oct 18..I started having unprotected sex on October 19 to October 28..is it possible I could get pregnant?

  • By Midwife @Tommys on 12 Nov 2018 - 16:31

    Hi Claud
    Any unprotected sex can cause pregnancy. If you are trying to avoid pregnancy, please use condoms which will protect against unwanted pregnancies as well as sti's.
    Take care, Tommy's Midwife

  • By India oates (not verified) on 11 Nov 2018 - 14:33

    Hey my name is india , I have irregular periods , and my period comes on and 3 months it comes back on some my last period Was September 25th and stayed on 5 days as usual and I have downloaded flo to see when I can ovulating and it said October 10th so I had sex on that day to the 12th , can I still get pregnant with irregular periods and pcos? or when should I take a pregnancy test

  • By Midwife @Tommys on 13 Nov 2018 - 12:37

    Hi India - thank you for your message. It is possible to conceive with PCOS and irregular periods, but you should visit your doctor/GP and discuss this in detail with them as well pre-conception advice too.
    Have a read of our pages on planning a pregnancy:
    https://www.tommys.org/pregnancy-information/planning-pregnancy/12-things-do-when-trying-baby

  • By Pearl Susanna (not verified) on 7 Nov 2018 - 22:37

    My last period was on 3 Oct 2018,I had unprotected sex with 3 different boyfriend.. 14,20 and 21 now I can't tell who's the dad

  • By Midwife @Tommys on 9 Nov 2018 - 14:27

    Hi Pearl,
    It will not be possible to tell who the father of your baby will be unless you have a DNA test, it is commonly done when the baby is born but can be done antenatally at a cost. It is also important that you are safe, if you are having multiple partners without contraception, you are at risk of sexually transmitted infections. If you would like to talk confidentially and need support then please do email us [email protected]
    Best wishes
    Tommy's midwife

  • By Poppy101 (not verified) on 6 Nov 2018 - 23:12

    My last period was around 16th October. I had unprotected sex 10 days later. Could I be pregnant?

  • By Midwife @Tommys on 9 Nov 2018 - 14:18

    Hi,
    If you are having intercourse without contraception then yes there is a chance of pregnancy. I would suggest that if your period does not come when due then to take a pregnancy test. In the meantime if you think you maybe pregnant or are having unprotected intercourse then it is important to be taking a folic acid supplement.
    Best wishes
    Tommy's midwife

  • By Nwosu Chioma (not verified) on 30 Oct 2018 - 16:55

    I had sex on the 8 of September and my period started on 21 of September, and I'm 6weeks pregnant how possible is this pls help me

  • By Midwife @Tommys on 2 Nov 2018 - 10:59

    Hi Nwosu,
    We calculate pregnancy dates by the first day of your last period, therefore if this was the 21st September this would make you about 6 weeks pregnant, if you have not had intercourse after this date then it could be possible that your last period was an implantation bleed if it was lighter and short than usual and you are more weeks pregnant than 6 weeks. Your dating scan will give you an accurate due date and how many weeks you are.
    Best wishes
    Tommy's midwife

  • By joanita (not verified) on 25 Oct 2018 - 07:55

    i had my periods on 11th of October and ended on 15th and i started having unprotected sex on 19th to 21st,is it possible to get pregnant

  • By Midwife @Tommys on 25 Oct 2018 - 14:04

    HI Joanita, Thank you for your comment.
    If you have been having unprotected sex without any form of contraception then there is every chance that you may fall pregnant. Wait and see if you miss you next period and then do a pregnancy test to check for pregnancy. Take Care, Tommy's Midwives x

  • By Pretty (not verified) on 24 Oct 2018 - 13:41

    hey ,i had my period on 04-10 and i did unprotected sex on 16th can i be pregnant

  • By Midwife @Tommys on 24 Oct 2018 - 14:13

    Hi Pretty
    If you had unprotected intercourse, then it is possible for you to conceive a pregnancy. Please see the link below how and when is best to take a pregnancy test.
    You can take a pregnancy test when and if your period is a week late
    https://www.tommys.org/pregnancy-information/planning-pregnancy/taking-pregnancy-test
    All the best
    Tommy's Midwife

  • By Gladys (not verified) on 18 Oct 2018 - 11:45

    Hi am Gladys , I received my period on 3rd -8th October, I had unprotected sex on 14th ,15th,16th $ 17th ,I am married and I want a baby... Could I be pregnant, then after 17th I experienced tender and breast ache which I usually have during my cycle ..kindly help

  • By Midwife @Tommys on 18 Oct 2018 - 11:56

    Hi Gladys, Thank you for your comment.

    As you have had unprotected sex during your cycle then there is every chance that you may be pregnancy. Wait and see if you miss a period and then do a pregnancy test to check for pregnancy. Take Care, Tommy's Midwives x

  • By ELAINE SALAZAR (not verified) on 9 Oct 2018 - 18:36

    I WAS OFF THE DEPO SHOT ABOUT MAYBE. 6 MONTHS MORE OR LESS. I HAD RELATIONSHIP WITH A FRIEND ON AUGUST 12. HAD MY PERIOD. ON AUGUST 18. AND HAD ANOTHER RELATIONSHIP WITH A REALLY CLOSE FRIEND. ON AUGUST 20TH. MY PERIODS ARE IRREGULAR SINCE I HAD BEEN USING THE DEPO I JUST WANT TO KNOW IF I GOT PREG WITH THE FIRST RELATIONSHIP,, OR THE SECOND????

  • By Midwife @Tommys on 11 Oct 2018 - 11:39

    Hi Elaine, Thank you for your comment.
    As your periods are irregular it is difficult to say when you ovulated and who would be the potential father to your baby. If you are unsure of how many weeks you are then we would suggest that you see your GP who can refer you for a dating scan to see how far you are in your pregnancy. Take Care, Tommy's Midwives x

  • By Juliet (not verified) on 6 Oct 2018 - 10:52

    My last menstrual date was 23th to 25th september and I had unprotected sex all through my period. Then after my period ended I had sex on the 26th, 27th and 29th is it possible for me to get pregnant

  • By Midwife @Tommys on 9 Oct 2018 - 12:10

    Yes, It is theoretically possible to get pregnant at any time during your cycle if you don't take precautions.

  • By Crystal (not verified) on 2 Oct 2018 - 20:04

    I started my period Sept 27 after not having one for over a year. Oct 2 I had unprotected sex and he ejaculated in me. I literally stopped bleeding in the middle of intercourse (not before or after). Is it possible to get pregnant as a result?

  • By Midwife @Tommys on 4 Oct 2018 - 16:22

    Hi Crystal, Thank you for your comment.

    If you have had unprotected sex then there is every chance that you could fall pregnant. Wait for your next period and if it is late then do a pregnancy test to see if you are pregnant. Take Care, Tommy's Midwives x

  • By Isabel (not verified) on 27 Sep 2018 - 15:20

    I had my period on the 9th for 5 days I had unprotected sex on the 13th the 17th and 18th could I be pregnant ?

  • By Midwife @Tommys on 27 Sep 2018 - 15:44

    Hi Isabel, Thank you for your comment.

    It is still very early to tell if you are pregnant if you only had your period on the 9th September but if you have been having unprotected sex with no other form of contraception then there is every chance that you may fall pregnant. We would advice that you should wait to see if you miss your period and then do a pregnancy test. Hope this helps, take care, Tommy's Midwives x

  • By Hellena (not verified) on 24 Sep 2018 - 08:54

    I got my periods 19 to 22 of September and i need pregnant..so which is the best date to have unprotected sex??

  • By Midwife @Tommys on 25 Sep 2018 - 15:02

    Thank you for your comment.
    You should try to have sex every 2-3 days throughout your cycle as this can maximise your chances of conception. Your most fertile time is around ovulation which occurs 10-16 days before the start of your next period. If you know when you ovulate each month you can give yourself the best chance of getting pregnant by having sex in the days leading up to ovulation. Continue having sex during ovulation. After this your fertile time will be over for that cycle.
    The following link has more information that you may find helpful-

    https://www.tommys.org/pregnancy-information/planning-pregnancy/how-get-pregnant

    Take care
    Tommy's Midwife

  • By Laeticia (not verified) on 23 Sep 2018 - 15:40

    I had my period on the 11-14 September and from that 14th I have been having unprotected sex till today the 23 September can I be pregnant?

  • By Midwife @Tommys on 25 Sep 2018 - 15:10

    You may be pregnant-you are your most fertile around ovulation which usually occurs 10-16 days before the start of your next period
    If you know when you ovulate each month you can give yourself the best chance of getting pregnant by having sex in the days leading up to ovulation. Continue having sex during ovulation. After this your fertile time will be over for that cycle.
    The best way to find out is to take a pregnancy test-some of these tests are very sensitive to hormone levels which change once you are pregnant and can be used even before you have missed a period

    Take care
    Tommy's Midwife

  • By Debby (not verified) on 16 Sep 2018 - 13:26

    Am having irregular menstruation ,what is the assurance that I can get pregnant, am about getting married and am sacred

  • By Midwife @Tommys on 17 Sep 2018 - 10:08

    Hi, It isn't possible to guarantee that you will have no problems conceiving. The best thing you can do is to lead a healthy lifestyle with good nutrition and exercise. Our new web tool #areyouready gives good advice about how to increase your chances of a healthy and happy pregnancy.

  • By Anonymous (not verified) on 14 Sep 2018 - 21:11

    I got my period on 27 may and have sex on the 3 June since June I didn't nt got my period

  • By Midwife @Tommys on 17 Sep 2018 - 10:12

    It would be sensible with these dates to do a pregnancy test or arrange to see your doctor. Best wishes

  • By Jasmine (not verified) on 7 Sep 2018 - 22:09

    Hi my last period was August 18-23 I have unprotected sex September 1-5 can I be pregnant?

  • By Midwife @Tommys on 12 Sep 2018 - 09:38

    Assuming that you have a 28 day cycle then you would be most likely to be fertile around those dates so conception is possible. I would suggest you do a pregnancy test to confirm whether you are pregnant or not.

  • By Ashley (not verified) on 7 Sep 2018 - 19:04

    Hi, so I recently just had unprotected sex on September 7th (today) I checked my period tracker and it let me know that today was my last day of being fertile. Is there a possibility to get pregnant on the last day of ovulation? So far I’ve read that it’s more likely to get pregnant within the first 24 hours of ovulation so I’m a bit confused on whether or not the last day of ovulation matters as well.

  • By Midwife @Tommys on 12 Sep 2018 - 09:31

    Your period tracker would only tell you when you are likely to ovulate, not the exact day of ovulation. Ovulation generally occurs 10-16 days before your next period-this is considered to be when you are most fertile-you can only get pregnant on the few days each cycle around ovulation, when an egg is released.The following link has more information for you-
    https://www.tommys.org/pregnancy-information/planning-pregnancy/ovulation-calculator

    Tommy's Midwife

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