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.


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


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Your stories of planning for pregnancy

  • Couple Amanda and Judd with daughter Shelbie


    I just knew that there were no guarantees for us when trying to conceive

    Amanda, 26, had irregular periods and she knew getting pregnant would be a challenge. She and her husband decided to become healthier when they were planning to have a baby. They now have a daughter called Shelbie.

  • Hayley, Sam and baby Amaryllis


    “One chance for a baby”

    Hayley, 27, and Sam, 28, a barista from Lincolnshire knew their health conditions would make conception a challenge. But they didn’t give up. Following fertility treatment, they now have a daughter, Amaryllis. This is their story.

  • Claire Gale


    “I knew I was ready to try again”

    Claire Gale, 30, and husband Mark, 32, from Bournemouth always wanted a family. Last year and 8 weeks into her pregnancy, Claire miscarried, but she trusted her body to tell her when it was time to try again for a baby.

  • Lauren with her baby Cherry


    Our emotional pregnancy journey

    Lauren, 33, from Essex, and her husband Victor, 33, struggled to conceive and endured a miscarriage and pre-eclampsia before they had their beautiful daughter Cherry.

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

    Was this information useful?

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    Please note that these comments are monitored but not answered by Tommy’s. Please call your GP or maternity unit if you have concerns about your health or your baby’s health.
    • By Midwife @Tommys on 5 Feb 2018 - 15:21

      Yes, There is no 'Completely safe time' as sperm can live for up to 7 days. If you think that you may be pregnant you can do a pregnancy test when your next period is due.

    • By Jess (not verified) on 29 Jan 2018 - 02:29

      Could I get pregnant if I'm on the pill and he pulled out? I haven't have my my period since September with the way my pills are?? Help?

    • By Midwife @Tommys on 29 Jan 2018 - 16:39

      Yes, most forms of contraception have a risk of failure. If you think that you may be pregnant. take a pregnancy test just to be sure.

    • By asana (not verified) on 25 Jan 2018 - 22:41

      had unprotected sex with the withdrawal method on my fertile day four and then took birth control injection later drink postinor 2 will i still get pregnant

    • By Midwife @Tommys on 26 Jan 2018 - 11:26

      Hi Asana,
      It is unclear from your message how long it was after intercourse you had the birth control injection and what type of injection this was. If it was a few days later then it may not have prevented a potential pregnancy. I would advise that if your period does not come when expected then to take a pregnancy test to be sure. Taking a test before this time may result in a false negative result. Take care, Tommy's midwives.

    • By Michelle (not verified) on 25 Jan 2018 - 21:18

      Hello my bf cummed in me 11 days before my period. My last period was on january 5. Do i have the chance of getting pregnant?

    • By Midwife @Tommys on 26 Jan 2018 - 11:15

      Hi Michelle,
      Yes there is a chance that you could be pregnant. Having intercourse without contraception means there will always be a chance of pregnancy. If your period does not come when due then it would be important to take a pregnancy test to see if you are pregnant. Taking a test before this time may result in a false negative. Take care, Tommy's midwives.

    • By Dineo (not verified) on 18 Jan 2018 - 10:16

      The first day of my last period was on the 26th of December was fertile/ovulated around the 9th until the 14th January and has sex everyday around those dates i know my next period is due on the 26th what are my chances that i might be pregnant coz from the 15th i have been spotting brownish pinkish discharge could it be implantation

    • By Davy (not verified) on 7 Jan 2018 - 16:02

      I had my menses on 15th dec and i had unprotected sex with d withdrawal method wt my boy friend on the 1st of January.. can i be pregnant?
      Please answer

    • By Midwife @Tommys on 10 Jan 2018 - 10:28

      Hi Davy
      The withdrawal method is not an effective method of preventing pregnancy or STI's! So please keep yourself safe by using contraception to prevent BOTH pregnancies and STI's if you are not trying to conceive. If you are pregnant, you wouldn't be more than 3-4 weeks pregnant at the most. So please do a pregnancy test in the next week to confirm this either way for your own peace of mind. Please take care of yourself
      Sophie,Tommy's Midwife.

    • By maria (not verified) on 6 Jan 2018 - 20:53

      hi, me and my bf had sex more than one time 3 days after my period is there a chance that i can get pregnant?

    • By Midwife @Tommys on 10 Jan 2018 - 10:21

      Hi Maria.
      If you and your boyfriend have had unprotected intercourse, at any time after your period, then you could potentially get pregnant yes. If you are not intending to become pregnant, then please do ensure you protect yourselves by using contraception. You can get free contraception for all sexual health clinics and GP surgeries across the country. Please take good care of yourself and feel free to email us if you need any more advice.
      Sophie,Tommy's Midwife

    • By nana (not verified) on 1 Jan 2018 - 13:44

      Can pills like ever green women formual,boost ovulation faster dan it was,blc I had my period 29 ND 30 just two days of Nov ND I has sex 3 dec ND am comfirm pregnt 2days ago is it possiable

    • By Midwife @Tommys on 4 Jan 2018 - 13:21

      Hi, Thank you for your comment.
      Your message is unclear so if you would like to contact the Tommy's midwives we would be more then happy to give you advice, please email [email protected] Take Care, Tommy's Midwives x

    • By Anonymous (not verified) on 17 Dec 2017 - 17:23

      I had a miscarriage over a month ago. It was my first pregnancy. During the month I conceived, we had sex every three days in the week I ovulated, which obviously worked. Now we're trying to conceive again and I know I'm putting so much pressure on myself to conceive. How can I get back to the relaxed woman I was when I conceived now that I'm aware of miscarriages and so desperate to get pregnant? I wasn't even trying before and I know I wasn't bothered either way. Now all that consumes my thoughts is getting pregnant again.

    • By Midwife @Tommys on 18 Dec 2017 - 14:46

      So sorry to hear about your miscarriage. I hope you are giving yourself time to recover. There is nothing magic that I can say to you except that you must try to relax and find some purpose in your life again. I completely understand that desperate desire to get pregnant - it's actually really common in women who have lost a pregnancy. Focus all that energy on getting yourself into the best state of health possible. Diet and exercise is the key. Also ensure that you are taking folic acid each day. I hope that 2018 will be a good year for you. Best wishes.

    • By Anonymous (not verified) on 17 Dec 2017 - 11:26

      I saw my period my period on the 10th of November when am I likely to get pregnant

    • By Midwife @Tommys on 18 Dec 2017 - 13:55

      For most women the egg is released about 2 weeks after the start of your period and this is around the time that you are most likely to conceive.

    • By Anonymous (not verified) on 13 Dec 2017 - 13:10

      My ovulation dates are from Nov 17-26. My boyfriend and I had unprotected sex last December 1 to 3. I should be getting my period last December 9, but is delayed for 5 days now. Ive been stressed for a while this past few days. Am i pregnant? Or is it just delayed by stress? I also took a start on a medication, just some multivitamins

    • By Midwife @Tommys on 13 Dec 2017 - 16:19

      Hi, Thank you for you comment.
      If you have had unprotected sex around the days of ovulation and now your period is late, then there is every chance that you may be pregnant. It would be advisable for you to do a pregnancy test to check for pregnancy. You can get these from any chemist or your local family planning clinic may offer free pregnancy testing. If you are pregnant then make an appointment to see your GP so that your can be referred to the midwife and your antenatal care can begin. It is great that you are already taking pregnancy vitamins. Good Luck, Take Care, Tommy's Midwives x

    • By bella (not verified) on 1 Dec 2017 - 02:08

      M a virgin but I have been fingered by my boyfriend.. I saw my menstruation on Oct n didn't see on Nov... A guy poured sperm into my vaginal.. Is there any way I can get pregnant

    • By Midwife @Tommys on 1 Dec 2017 - 11:58

      If a guy has poured sperm into your vagina then there is a chance that you could be pregnant, if your period has not come then take a pregnancy test which will show whether or not you are pregnant. If you would like to talk further in a confidential place with a midwife then please do email us [email protected] or call 0800 0147 800, we are here Mon-Fri 9-5pm to support you.

    • By mariam (not verified) on 26 Nov 2017 - 07:36

      Hi i tried to conceive but it not working out for me.I alway have unprotected sex at when i thought i could be pregnant but not.Pls could it be some problem

    • By Midwife @Tommys on 28 Nov 2017 - 09:32

      Thank you for your comment
      I'm sorry to hear that it is taking you a while to conceive. There could be several reasons why it's taking longer-for example, your age or underlying health conditions. I would suggest that you speak to your GP who can arrange some tests or refer you to a an infertility clinic if appropriate. However your GP may not refer you until you have been trying for more than a year

      I have attached some links that you may find helpful:


      Take care
      Tommy's Midwife

    • By nkongho (not verified) on 17 Nov 2017 - 13:48

      Hi ihad my period on 16-20 october and i had unprotected sex on the 25and had protcted sex on 27 october and 4 novemb i was supposed to menstrate on the 15 bt it did not come and i urinate toomuch am i pregnant

    • By Midwife @Tommys on 17 Nov 2017 - 16:28

      Hi, if you are having unprotected sex and you have missed a period then there is a high chance that you could be pregnant. The only way to know for sure is to take a pregnancy test. Take care, Tommy's Midwives

    • By Anonymous (not verified) on 10 Nov 2017 - 02:21

      I had unprotected sex on the 4th and 5th of May 2017. Since then I was experience morning sickness. And I had protected sex on the 29th of May 2017. I bleed for 1 day on the 17th of May 2017 what I think was implantation bleeding. Baby due 20th of Feb 2018.

      My last proper period was the 1st of April -11th of April 2017. Midwife is going from the 17th of May for the baby due date, wanted to know when did I conceive.

    • By Midwife @Tommys on 10 Nov 2017 - 10:35

      It is very difficult to tell you when you conceived exactly. If you have had a scan then this is the due date that will be used officially and is the most accurate. Using the due date of the 20th February 2018 then likely conception if you have a regular 28 day cycle would be the last week of May. However if you feel that the 17th of May was an implantation bleed and that your last full period was the 1st of April then conception would have been likely in the middle of April. However to reiterate that your scan date should be used as your most accurate due date.

    • By Anonymous (not verified) on 8 Nov 2017 - 03:25

      I had my period on 3rd Oct 17 i was only on for that one day I had unprotected intercorse with 2 guys 4 days apart it was confirmed by my doctor on 1st November 17 that I am pregnant but how do I know for sure which one is the dad to my baby

    • By Midwife @Tommys on 8 Nov 2017 - 13:28

      Hi, thank you for your post. The only way to know for sure which partner is the dad to your baby is by doing a paternity test after your baby is born. You would need to pay for this service.
      Have a look at the information on this link
      There is also the option of having a prenatal paternity test but this is very expensive (approximately £900) whereas after your baby is born the test is much cheaper.
      I am sorry that you are in this situation and wish you a good pregnancy. If you need someone to listen we are here for you so please give us a call on 0800 0147 800
      Anna-Tommy's Midwife

    • By Ninnie (not verified) on 25 Nov 2017 - 22:43

      Is to wait tell the baby is born . And take a DNA test online it's $80 something not bad . It will be sad for ever wanted to be the father but yeah DNA test is your option

    • By Sammie (not verified) on 15 Oct 2017 - 22:06

      I should have started my period on the 27th of sept 2017 but didn't start till the 30th I did have unprotected sex on the 30th before I noticed light bleeding with my somewhat boyfriend I've used the calendar about and it says my most fertile days are between 11th - 17th of this month I had unprotected sex on Friday 13th with the same man and now 2 days later I'm getting back pain and period like cramps that I don't usually get in between cycles what could this mean

    • By Midwife @Tommys on 16 Oct 2017 - 11:15

      Hi Sammie
      It is difficult to know what could be causing the back pain and cramps following your period. It is possible to become pregnant at any time of your cycle if you have unprotected sex as sperm can survive for up to 7 days. It might be sensible to wait another week and do a pregnancy test to be sure and put your mind at ease. Also, cramps and abdo pain, can be caused by UTI's which can be bought about by intercourse. So if you have any itching, stinging or burning when you pass urine, you may need to go to your GP for them to test your urine and potentially start some antibiotics. Please take care of yourself

    • By yami (not verified) on 13 Oct 2017 - 14:47

      I had my periods on 15 of sep And had unprotected sex on 3 oct, it was a pull out method we wiped the sperm away with tissue and again we had sex right after the pull out and just after that i had one dose of unwanted pill and today is 13 oct n i just got my period. Is there any chance that i'll might be pregnant???? Plz reply

    • By Midwife @Tommys on 16 Oct 2017 - 11:03

      Hi Yami
      Firstly, i want to inform you that the "pull out method" is not an effective way to prevent pregnancy - it is not a type of contraception. Sperm can still be present is pre-ejaculate fluids and so pregnancy is then still possible. In addition, the fact that you had intercourse again after ejaculation, with or without wiping yourself with tissue means that a pregnancy is still possible as it is likely that sperm has still entered the vagina. Also, this does not protect you from sexually transmitted diseases. Having taken the morning after pill and having had your expected period arrive, it would suggest that you are not pregnant as you would not get a period if you were pregnant.
      Please take care of yourself and consider using safe contraception methods in future to protect yourself from unwanted pregnancy and STI's

    • By Anonymous (not verified) on 10 Oct 2017 - 16:32

      My last period was sept 16th. We didn't have sex until oct 2nd. Do you think I missed ovulation?

    • By Midwife @Tommys on 11 Oct 2017 - 14:12

      Hi, It is possible that you missed ovulation but remember that humans don't always get pregnant straight away and it may be that it will take a few months before you conceive.

    • By Mira (not verified) on 9 Oct 2017 - 10:21

      Pls am trying to get pregnant, my period started on the 24th of September and ends on 27th of September, pls when am I likely to ovulate

    • By Midwife @Tommys on 11 Oct 2017 - 14:09

      Ovulation is usually about 2 weeks after the period starts, i.e midway through your cycle. This can though vary from one woman to another. Check out our 'Top tips for conception' https://www.tommys.org/pregnancy-information/getting-pregnant/top-tips-conception. Good luck

    • By Anonymous (not verified) on 3 Oct 2017 - 02:02

      Hi there,
      My husband and I decided we wanted to start TTC. I finished my last pack of Bc pills on 9/12 and had my period on 9/15-9/19. I have been taking ovulation tests everyday a week since my last period. All the tests have come up negative. When can I expect a positive ovulation test?

    • By Midwife @Tommys on 3 Oct 2017 - 10:31

      thanks for your post. I think as you have been on the pill it would be good to get an idea of your natural cycle length first by noting on a calendar how many days your period lasts for and how long until your next period begins. Ovulation usually occurs 10-16 days before your next period so having regular sex throughout your cycle when TTC is advised. In the link below there are other signs to show that you are ovulating so that you don't need to use up all your ovulation tests.
      It is also good to remember that 80% of couples get pregnant within a year and 90% within 2 years.
      Good luck!
      Anna-Tommy's Midwives

    • By Anonymous (not verified) on 1 Oct 2017 - 08:45

      My last menstruation was on the 15th to 17th of September 2017. I have been having unprotected sex since then, I did my pregnancy test (blood) on the 29th of September, it was negative. Can I still get pregnant with this few days to my messes?

    • By Midwife @Tommys on 2 Oct 2017 - 12:15

      The earliest that you can expect a positive pregnancy test would be mid October. You would expect to ovulate about 2 weeks after your period and it would take another 2 weeks before a positive pregnancy test is possible.
      Take care x

    • By felicity (not verified) on 28 Sep 2017 - 18:48

      i saw a blood shed on 4th of september and stoped flow on the 9th and 10th of september, i saw a white raw egg on the 19th and 21st of september.i had sex on the 21st of september.it is possible to have been pregenant with a baby boy.

    • By Midwife @Tommys on 29 Sep 2017 - 12:08

      It is very difficult to know whether a spontaneous pregnancy will result in a baby boy or girl. Therefore I am unable to say. You will however find out the sex of your baby around 20 weeks at your scan.

    • By Anonymous (not verified) on 27 Sep 2017 - 10:16


      I recently (28th August 2017) underwent a D&C operation for a missed miscarriage. Our baby Robin measured 8 weeks when we should have been 12+1. Yesterday I started my first menstrual cycle and we were advised to try again after my first cycle. Is there anything I can do to help lower my chances of another miscarriage this time around. This was my second miscarriage. I had one many many years ago but never had any medical intervention as I was young and afraid. My husband and I desperately wanted a baby and after lots of in-depth conversations we wish to fall pregnant asap again.

    • By Midwife @Tommys on 27 Sep 2017 - 12:29

      Hi Thank you for your comment.

      We are sorry to hear about your losses it can be a very difficult time for you and your husband and it is understandable that you want to start to try again now that you feel ready too. The best things that you can do is to keep taking pregnancy vitamins, eat a healthy diet and if you smoke or drink alcohol then try and reduce this as much as you can or the ideal would be to stop altogether. Doing these things will give a pregnancy the best start possible. Try and get enough rest and be kind to yourself as well. Hope this helps, if you need any further advice please contact the Tommy's Midwives on 0800 0147 800 9am-5pm Monday to Friday or email [email protected] Take care, Tommy's Midwives x

    • By Ammu (not verified) on 26 Sep 2017 - 14:16

      My last period of first day is Sep 1st and end was on Sep 5th. I got spotting once on Sep 15th and had a unprotected sex on Sep 17th.
      9/25 - I had uterus and abdominal pain and also backpain,felt nauseous and little dizzy. Today(9/26), having severe lower back pain.
      IS there any changes are there to get pregnent?

      My last period:
      June: started on last week - ends on July 1st
      Aug: started and ended in 1st week
      Sep: started Sep 1st - ended on Sep 5th

    • By Midwife @Tommys on 26 Sep 2017 - 14:34

      Hi Ammu.
      It would probably be sensible to do a pregnancy test if you have had unprotected sex- you may need wait another week or so for the test to accurately show if there is a pregnancy there or not. Abdominal pain, nausea, dizzyness can be a sign of pregnancy, but this can also be attributed to many other things too. So it is hard to know without doing a test. Take good care of yourself! All the best!

    • By Anonymous (not verified) on 25 Sep 2017 - 10:32

      My last period start date was 30th Aug I had unprotected sex on 19th September could I be pregnant? My cycle is normally 32/33 days. Please help?

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