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 conceived during these times.

Take our pregnancy planning quiz

Ovulation calculator

What was the first day of your last period?

What is your average cycle length?

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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 maximise the possibility of a 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.

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.

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.

See what fertile cervical mucus looks like on the BabyCentre website.


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.

Find out more in our getting pregnant FAQs


  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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  • By Tyra (not verified) on 25 May 2018 - 00:12

    Hey.... I know this may sound stupid but just read it please.... My last period was on march 14 i had sex on march 28.. Missed my period for the month of April and then on may 1 it came for tbe 7 days ... Im still worried ... No symptoms negative pregnancy test but my stomach looks bigger in the upper part i just don't understand..

  • By Midwife @Tommys on 25 May 2018 - 10:28

    If you have had a full period since intercourse and having negative tests it is very unlikely that you are pregnant. You said that the upper part of your stomach is looking bigger, again this would be unlikely to do with a pregnancy. If you are having any pain or discomfort with your stomach then do see your GP for a review.
    Best wishes, Tommy's midwives

  • By Joy (not verified) on 21 May 2018 - 02:19

    Last period was 28-4 Last month.Had unprotected sex on 19th and 20th..can I concieve

  • By Midwife @Tommys on 21 May 2018 - 16:40

    Yes, This would be within the fertile time of your monthly cycle.

  • By Millie (not verified) on 17 May 2018 - 17:09

    HI?i my last period was 31st april,and i had unprotected sex on 6 may but i took a pill before 72 hours?? On date 20 to date 2 may this month,my husband came and we are having sex without protection but he was withdrawing the sperms and pouring around my pussy,so i was feeling funny ,nusea,vomiting ,tired and feeling sleep,i went to the hospital they told me am pregnant,i was expecting my period date 25 i didnt get,so could this pregnant for date 6 april which i took a pill,or could it for my husband from date 20 april to date 2 may which was uprotected but he was withtawing the sperms??? Please reply?

  • By Midwife @Tommys on 18 May 2018 - 16:23

    Hi Millie,
    The morning after pill is not 100% effective, like any contraception, so whilst you took it within 72 of intercourse which is as advised, this will not always guarantee to prevent pregnancy. Additionally, the withdrawal method of contraception is not 100% either, therefore it is possible that you conceived on either of these two occasions.
    Best wishes
    Tommy's midwives

  • By Jya (not verified) on 15 May 2018 - 03:28

    Hi! I had my first day of my last period on April 26,2018 and i had unprotected sex May 12-13,2018. My cycle is regular an average o 27-28 days.How high is the chance of getting pregnant

  • By Midwife @Tommys on 15 May 2018 - 10:05

    Hi Jya
    Any unprotected intercourse has the potential to create a pregnancy.
    Try using our ovulation calendar to work out the optimal times for you to try to conceive.
    All the best
    Sophie,Tommy's Midwife

  • By Elle (not verified) on 10 May 2018 - 15:43

    I had my last period from april 11-16, 2018 and I had unprotected sex on april 18 & 20 and then I had unprotected sex again on May 8 & 9. My period is regular. Can I be pregnant?

  • By Midwife @Tommys on 10 May 2018 - 15:51

    Hi Elle
    Any unprotected intercourse can lead to pregnancy. If you need to talk any of this over, it might be best to call us on 0800 0147800 or email us privately (this is a public page) on [email protected]
    Take care
    Tommy's Midwife

  • By Anon (not verified) on 5 May 2018 - 02:23

    Hey I have been on the merina since August last year (2017) I was still having periods that lasted like three four days. My last period was early March (2018) it is May 4, 2018 and for the past three days I’ve had soar boobs, I’ve been drowsy, cramps are worse than usual, a little faint and had a little brown spotting. Not to mention I’ve been burping constantly. I’ve never had soar tender boobs before a period. I took two tests yesterday but came up negative. Today I look and there’s a faint line and a darker line. My test was still wet and wasn’t dry. Can you help me please??

  • By Midwife @Tommys on 10 May 2018 - 11:02

    Hi there
    It does take the body a while to regulate itself after having the Mirena coil removed. This can take up to a year. It sounds as if you may be experiencing early pregnancy symptoms. It might be best to wait another 5-7 days and repeat the test as tests that are done very early on in pregnancy (in the first 1-4 weeks) can often be difficult to detect as the body's HCG levels are still buidling and are not always picked up by home pregnancy tests.
    Leave it a few more days, retest and i am sure the result will be more easy to read. If you have any more queries, feel free to call us on 0800 0147800
    Sophie,Tommy's Midwife

  • By Mercy (not verified) on 1 May 2018 - 14:10

    I had my last period from 6-10 of April, 2018 and had sex on 15 of the same month, am I pregnant?

  • By Midwife @Tommys on 1 May 2018 - 16:12

    Hi Mercy,
    if you have regular cycles and you are having unprotected sex you might be but you will need to do a pregnancy text to confirm this, this month. You can get pregnancy test that you can do before your period is due.
    Warm wishes,
    Anna-Tommy's Midwife

    Take care

  • By Lili (not verified) on 24 Apr 2018 - 14:56

    I sure my period on thirty first March it stop on nine April,it start again on Twenty first April is it normal or are my pregnant

  • By Midwife @Tommys on 26 Apr 2018 - 16:09

    Hi Lili, Thank you for your comment.

    If you have been having unprotected sex then there is every chance that you could become pregnant. Do you have irregular periods? If this bleeding is unusual for you and you think you may be pregnant then do a pregnancy test. If this is negative you can always go and see your GP if you are worried about irregular periods. Spotting in early pregnancy is normal however, if needs to be confirmed if you are pregnant first. Hope this helps. Take Care, Tommy's Midwives x

  • By berry (not verified) on 20 Apr 2018 - 21:25

    I had my periods on 1 April to 5 april i had sex without my fiancée on 18 April can i be pregnant plss

  • By Midwife @Tommys on 23 Apr 2018 - 14:59

    Hi, Yes you could get pregnant at any time if you are not using contraception, but the most fertile time would be between 12th and 20th April. Hope this helps to explain. Take care

  • By yetunde (not verified) on 18 Apr 2018 - 17:17

    can I get pregnant 10days before my period I have my period on 22 to 27 march and had unprotected sex on 6and7 is it possible to be pregnant

  • By Midwife @Tommys on 19 Apr 2018 - 15:45

    Hi, Thank you for your comment.

    If you have had unprotected sex at any time during your cycle then you have a chance of falling pregnant. Around 14 days into your cycle would be the most fertile time but again it can be at any point without the use of contraception. Hope this helps. Take Care, Tommy's Midwives x

  • By MC (not verified) on 12 Apr 2018 - 17:20

    Hi, i was on birth control pills from Dec 9 2016 up to Mar 1 2018. LMP was Feb 26, 2018. We had sex on the last day of pill, my expected period for march was Mar 26, 2018. As of today I am in cycle day 47. Is it possible that I am pregnant? Last HPT was April 4, negative result. Please answer. Thank you so much!

  • By Midwife @Tommys on 13 Apr 2018 - 10:05

    There is a possibility that you could be pregnant, however a home pregnancy test would likely detect a pregnancy several days after a missed period, when you took it. Sometimes when you stop or change contraception, it can take a couple of cycles to return to what is normal for you as your hormone levels are adjusting. I would suggest to repeat the pregnancy test a week after your last, if this is negative and your period has not yet returned then you may want to see your GP for review.
    Best wishes, Tommy's midwife

  • By sunday (not verified) on 12 Apr 2018 - 14:15

    my period started and lasted for 5days.it started on the march 27 to march 31.i had unprotected sex on the 1st April. what are my chances of pregnancy?

  • By Midwife @Tommys on 12 Apr 2018 - 14:43

    Hi Sunday
    Any unprotected intercourse has the potential to cause a pregnancy. So if you are not trying to conceive, then it is really important for your long-term reproductive health, to ensure that you use contraception to prevent yourself from both sexually transmitted infections, as well as unplanned pregnancy.
    Please feel free to call us on 0800 0147800 if you wish to discuss this further.
    All the best
    Sophie, Tommy's Midwife

  • By Anonymous (not verified) on 10 Apr 2018 - 17:03

    I had my period on 22 of March and i had sex on 6 will i be pregnant

  • By Midwife @Tommys on 11 Apr 2018 - 09:04

    Hi there. It might be sensible for you to call us on 0800 0147800 as we will need more information from you to be able to fully answer your question.
    Look forward to hearing from you.
    Sophie, Tommy's Midwife

  • By Kloie (not verified) on 7 Apr 2018 - 22:09

    I had my period March 31 to April 3 I had unprotected sex during period and right after it ended which would be April 4, 5, & 6. Is there any chance I can be pregnant ?

  • By Midwife @Tommys on 9 Apr 2018 - 15:48

    It is unusual to get pregnant during your period but it is not unheard of as the sperm can remain alive for several days. Have you done a pregnancy test?

  • By Regi (not verified) on 5 Apr 2018 - 11:40

    My last mense were on dec 2017,Jan and feb i didnt receive,so i took the 21 days pills so that my periods can come back,they come on day 28 (19th march and ended on 23)then I baby danced on cycle day 13,14,15,16,could I be pregnant? I really want to conceive

  • By Midwife @Tommys on 6 Apr 2018 - 12:37

    Hi Regi,
    If you are having regular sexual intercourse without contraception then you could be pregnant however you would need to take a pregnancy test. It would be a little early to take the test, and you may get a false negative result. It would best to wait until your next period would be due, then if you are late to take a pregnancy test then. In the meantime, if you are trying to conceive then we would advise for you to be taking a folic acid supplement.
    Best wishes, Tommy's midwives

  • By Tessy (not verified) on 4 Apr 2018 - 17:53

    I started my period on the 26th of March and had unprotected sex with my husband on the 27th of March my period stopped the next day.. Does that mean I will be pregnant?

  • By Midwife @Tommys on 5 Apr 2018 - 10:33

    Thank you for your comment. It is possible to become pregnant while having your period, however it is unlikely that because your period stopped the next day means that you are pregnant as it takes a few days for pregnancy hormones to develop.
    You may want to wait to see if your next period is normal before doing a pregnancy test; alternatively there are tests you can do that show if you are pregnant even before you have missed a period.

    Take care
    Tommy's Midwife

  • By Asia (not verified) on 3 Apr 2018 - 17:38

    Hello, I got off birth control 12.20.17. I have a 30 day cycle my lmp 3/18/18 & lasted for 6 days I had sex 3/25,3/27,3/29 & 4/1. I felt pain in my left side on 3/31 which I think was ovulation (not sure). I'm just confused and frustrated have been trying since ending bc really hoping I conceived this time. I guess my question is based on the days I had sex is it possible for me to still conceive after bc & the pain I felt was that ovulation & did the sperm have time to make it to the egg since last session was 4/1?

  • By Curious (not verified) on 31 Mar 2018 - 22:14

    I had gone without sex for nine months then I ended up getting my cycle on March 12 for 3 days.i have since March 15th have been sexually active almost every day what are the chances I am pregnant I'm asking cause I'm kind of having a feeling like I am cause I been really tired and having alot of same symptoms I had with my daughter

  • By Midwife @Tommys on 5 Apr 2018 - 09:46

    If you have been having regular sexual intercourse without any contraception then there would be a chance that you could be pregnant, if your period does not come when due then you can do a pregnancy test to see if you are pregnant. In the meantime if you are trying for a pregnancy or having sexual intercourse without contraception then we would advise for you to be taking a folic acid supplement.
    Best wishes, Tommy's midwives

  • By Sola (not verified) on 26 Mar 2018 - 18:28

    had sex 15th of March 6 to 5 days after ovulation n my period is due sinx Saturday 24th of march and I'm yet to see it

  • By Midwife @Tommys on 27 Mar 2018 - 11:52

    Thank you for getting in touch with us at Tommy's.
    Ovulation tends to occur around the middle of your menstrual cycle – usually about 2 weeks after the first day of your cycle, but this can vary depending on how regular and long your cycle is.
    It is usual for a woman to ovulate around 10 -16 days before their next period is due, the time of this depends on the length of her cycle, so in a 28 day cycle she would usually ovulate around Day 14. Sperm can live up to 5 days, so you can conceive 12-24 hours post ovulation. Some women also ovulate twice in their cycle. If your period is late it would be a good idea to do a pregnancy test.
    Warmest wishes
    Anna-Tommy's Midwife

  • By JAMM (not verified) on 20 Mar 2018 - 02:46

    Hi! I had my last period on Feb 22 and ended on feb 25. I had unprotected sex on March 12. My period is regular but lately I was feeling nausea. I vomit after my meal for 3days long. I also don't like some smell like the smell of fish w/c is not normal for me. I also crave for something. Last March 18 I felt my back and legs cramping. Is it a sign that I am pregnant?

  • By Midwife @Tommys on 21 Mar 2018 - 11:47

    Hi, there is a possibility you could be pregnant however the only way to know for sure is to take a pregnancy test, I would suggest to do this if your period does not come when due as doing a test prior to this make result in a false negative.
    Best wishes, Tommy's midwife.

  • By Anonymous (not verified) on 10 Mar 2018 - 22:18

    Hi,I had unprotected sex on my ovulation days then took contraceptive pills a week after that.now I have missed my periods for 3days now.
    Is it possible I am pregnant?please help

  • By Midwife @Tommys on 12 Mar 2018 - 12:08

    Hi, Best thing to do is to take a pregnancy test. If it is positive see your GP as soon as you can to discuss your options.

  • By My name is sund... (not verified) on 7 Mar 2018 - 17:59

    My period was 25feb 2018 stop28 i have sex with my husband on 28;1;2;3;4 nd 6 will i be pregnant?because i nd my husband need a child nd if my husband sperm inters inside my body it melt wat causes it pls?

  • By Midwife @Tommys on 8 Mar 2018 - 11:57

    Hi, Thank you for your comment.

    If you have been having unprotected sex then there is every chance that you may fall pregnant. You need to wait and see if you miss your next period. If you do then the next step would be to do a pregnancy test to confirm if you are pregnant. I cannot tell you if you are pregnant at this time as it is too early but missing your period would be the first indication to do a test. Hope this helps, Take Care, Tommy's Midwives x

  • By Baby andre (not verified) on 1 Apr 2018 - 17:52

    My period came on January 28and end the 3 of February and I have not got a period as yet and am wondering if it's because of my still birth last year November why this is happening .but no signs of pregnant systom

  • By Midwife @Tommys on 5 Apr 2018 - 12:41

    Thank you for your comment. I am sorry to hear about your loss and hope you are getting support with your recovery from this.
    I would suggest doing a pregnancy test even though you do not have any signs of pregnancy. Periods can be irregular when they start again after a pregnancy but it would be sensible to do a test if you think you could be pregnant again.

    Take care
    Tommy's Midwife

  • By Tracey (not verified) on 5 Mar 2018 - 14:09

    I had my period on feb 26 to march the 3rd they are usual 7 days long (the month of feb only goes to the 28). I dont know why it only lasted 6days. My periods aint regular ...i had sex on march 3 and 4 unprotected with my boyfriend could i be pregnant? Ive also got 4kids already .and yes we want to have another baby .

  • By Midwife @Tommys on 5 Mar 2018 - 16:05

    Hi Tracey,
    If you are having unprotect sex then there is always a chance that you could be pregnant, therefore if your next period is late then I would advise for you to do a pregnancy test. If you are trying to conceive then I would advise that you are taking a folic acid supplement if you are not already. Good luck!

  • By Tori (not verified) on 4 Mar 2018 - 23:36

    Hi my period usually comes around every 24 days, I ovulated (according to Flo app) on 14th had sex 2 days before and 1 day after, have taken test so many times all negative, but 4 days late, I'm confused as to when I can test? I got told that if I am I would be 4 weeks 3 days from date of last period, but fetal size is actually only 2 weeks 3 days,.. Have got milk in my breasts, a little tender, felt a bit sick, sore lower back, but no Pms symptoms I usually get like a week before period is due.. last child was 6 years ago, only taking folic acid, no contraception..

  • By Midwife @Tommys on 5 Mar 2018 - 16:08

    Hi Tori, it could be that it is just a little early and your hormone level is not yet high enough to show a positive test. I would advise to wait at least 2-3 days and repeat the test. It is great that you are taking folic acid and that you are having pregnancy symptoms, this is showing a good chance that you are pregnant. Best wishes, Tommy's midwives.

  • By Shan (not verified) on 2 Mar 2018 - 00:53

    My last period was on Jan 27 I started taking Errin bc on feb 1 and I’ve finished the pack on the 28th I haven’t gotten my period yet and me and my husband want a baby born in December my periods a irregular and I didn’t start the new pack I’m worried that I will get my period late and will unable to have a baby due in December what other options do I have since I’ve missed my ovulation dates?

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