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.


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.


  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 kelly (not verified) on 13 Aug 2018 - 08:46

    I had my period on August 2nd to 4th 2018. I have unprotected sex with my partner from 6th to 12, can I be pregnant. and I don't know when is my Ovulation days that's why I want to have sex till 19th of August. Can someone calculate it for me and tell me my Ovulation days and am 28 days cycle

  • By Midwife @Tommys on 15 Aug 2018 - 12:43

    Hi Kelly
    Any unprotected intercourse can result in pregnancy.
    If you are not trying to conceive, then i suggest that you use contraception.
    You will need to wait until your next period is due before doing a pregnancy test as you only had intercourse last week so it is too early to tell. You can use the ovulation tool -see below- to work out roughly when you may ovulate.
    All the best
    Tommy's Midwife

  • By Jaykey (not verified) on 7 Aug 2018 - 20:04

    Hi I am Jaykey... i had a baby on July 25, 2018 by operation. Yesterday I had an unprotected sex with my husband. Will it lead to pregnancy?
    Plz plz plz... rply

  • By Midwife @Tommys on 9 Aug 2018 - 15:55

    Hi Jaykey, thank you for your comment.
    If you are not using any form of contraception and having unprotected sex then there is every chance that you may become pregnant. We would suggest that if you don't want to become pregnant then you need to use a form of contraception in the future. Take Care Tommy's Midwives x

  • By Kara (not verified) on 9 Jul 2018 - 05:02

    I had my period last May 7 and then I had unprotected sex last May 30 and 31. I did have some sort of mens last June 9. Can I be pregnant?

  • By Midwife @Tommys on 9 Jul 2018 - 11:26

    Hi Kara, It is only possible to confirm a pregnancy at this stage by dong a pregnancy test. If you think that your last period was unusual and that you have had unprotected intercourse, it would be sensible to do a test.

  • By dinah (not verified) on 8 Jul 2018 - 08:56

    My period started on the 7th June and I had unprotected sex on the 2nd july n i haven't seen my period as at today, 8th July meanwhile my predicted date of my next period was suppose to be 5th july

  • By Midwife @Tommys on 9 Jul 2018 - 11:21

    In order to confirm a pregnancy at this stage, you would have to do a pregnancy test. The test will confirm or deny that the pregnancy hormone is present which is needed to sustain a pregnancy.

  • By Gift (not verified) on 26 Jun 2018 - 08:09

    Hi I'm gift, I had my period on 7 to 10 of June, n I had sex on the 17 , can I be pregnant.

  • By Midwife @Tommys on 28 Jun 2018 - 11:12

    Thank you for your message.
    If you think you might be pregnant, I would advise doing a pregnancy test. Ovulation usually occurs 10-16 days before the start of your next period and you are fertile at this time.It is possible you could be pregnant if you have a short cycle.
    I have attached 2 links with more information for you:-


    Hope this helps
    Tommy's midwife

  • By Adrianna (not verified) on 11 Jun 2018 - 02:51

    Hi my names adrianna I had my period on May 8th 2018 and stopped on May 13th 2018 , I had intercourse on May 24th 2018 , I’ve been searching up my ovulation days on the internet and it shows my most fertile days are May 23rd - May 29th can I be pregnant or no I don’t know , and on June 4th I thought I was starting my period because I started bleeding only when I used the bathroom and I would have only alittle bit of blood on my underwear and blood when I wipe and it stopped on June 6th 2018 could I be pregnant

  • By Midwife @Tommys on 11 Jun 2018 - 16:14

    Hi Adrianna, I would suggest that you do a pregnancy test to check. Take care

  • By cynthia (not verified) on 7 Jun 2018 - 15:52

    I saw my period of d 16 of may and i have sex on the 29,1,4 can i get pregnent

  • By Midwife @Tommys on 8 Jun 2018 - 12:49

    Hi Cynthia,
    if you are having intercourse without contraception then yes there is a chance that you could be pregnant. I would advise for you to take a pregnancy test if your period does not come when due. In the meantime if you are having unprotect intercourse then we would advise for you to be taking a folic acid supplement.
    Best wishes
    Tommy's mdiwife

  • By i tinyiko mosiya (not verified) on 30 May 2018 - 21:51

    My peroid came on the 2 may till 5 it came back again on the 28 may to 31still shock am i preg

  • By Midwife @Tommys on 1 Jun 2018 - 10:23

    It is difficult to know what is happening, have you done a pregnancy test? This might help to clear things up, however if this is negative then repeat the test in about a week to be sure of an accurate result.
    If you are trying for a pregnancy then we would advise for you to be taking a folic acid supplement.
    Best wishes
    Tommy's midwife

  • By Lee-an (not verified) on 30 May 2018 - 00:56

    Hello my least period was on the 26th of April on the 18tg of may I had sex and he came out side , today is the 30th of may and I still did not get my period but I have period cramps feeling.

  • By Midwife @Tommys on 30 May 2018 - 16:00

    Hi Lee-an
    Any unprotected sex can potentially cause a pregnancy. So if you are not planning to become pregnant, you need to use contraception to protect yourself from both sexually transmitted infections, and unwanted pregnancy. The "pull out" method is not a safe method of contraception at all.
    If your period is late, then i would advise you take a pregnancy test around 5- 7 days after your period was due to get the most accurate result pregnancy test result. Taking a pregnancy test before this time could give a false negative reading.
    Please take good care of yourself
    Sophie,Tommy's Midwife

  • By Ace (not verified) on 28 May 2018 - 12:14

    I had my periods on 25 April and had unprotected sex on 4 May and recently I haven't had my periods could I be pregnant?

  • By Midwife @Tommys on 29 May 2018 - 11:35

    Hi Ace
    Any unprotected sex can result in pregnancy. Please take a pregnancy test if your period is 7 days late for the most accurate test result. Taking a test before 7 days after a late period can give a false negative result.
    All the best
    Sophie,Tommy's Midwife

  • By Sarah (not verified) on 27 May 2018 - 05:39

    My period is every 23 days. My period always last 3 days. It came on the 18th/20th. I had sex on the 21st. And today is the 27th. Could i be pregnant.

  • By Midwife @Tommys on 29 May 2018 - 11:32

    Hi Sarah
    Any unprotected sex can result in a pregnancy, no matter where in your cycle you are.
    If you are not trying to conceive, please use contraception to protect yourself from sexually transmitted infections as well as anunwanted pregnancy.
    If you are actively trying to conceive, then it is best to take a test 7 days after a missed period for the most accurate result. And you might wish to consider taking pregnancy vitamins to prepare your body for a healthy pregnancy.
    All the best
    Sophie,Tommy's Midwife

  • By Martha Joseph (not verified) on 26 May 2018 - 19:42

    I had my period in May 2 but today the 26 I had not had my period should I be pregnant n how long should I wait before I take a test

  • By Midwife @Tommys on 29 May 2018 - 11:26

    Hi Martha
    If you have not seen your period by 7 days after the date that it is due, then you should do a pregnancy test for an accurate positive or negative result. Taking a pregnancy test anything before 7 days after a missed period can give you a false negative result.
    Sophie,Tommy's Midwife

  • 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

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