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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    Amanda, 26, and husband Judd, 29, from Essex, adopted a healthier lifestyle when planning to have a baby. They now have a daughter called Shelbie.

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    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.

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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 14 Aug 2017 - 15:53

      The 'pull out' method is not a reliable method of contraception. however it is too soon to know whether you are pregnant. Can I suggest that you seek advice from your GP or sexual health clinic. They will be able to assess your needs and help you decide on your best options.

    • By Anonymous (not verified) on 10 Aug 2017 - 04:52

      My period start 21st month of july. Ends 25th. Then i have unprotected sex in 26th.. Is it possible to get pregnant?

    • By Midwife @Tommys on 10 Aug 2017 - 12:18

      Hi, Thank you for your comment.

      If you have unprotected sex and you are not on any other form of contraceptive then there is always a chance that you could get pregnant. On average the most fertile time for a women would be around day 14 of her cycle but this can be different for everyone. It would be advisable that you wait and see if you miss your period, if you do then you will need to do a pregnancy test to see if you are pregnant or not. If you are still concerns then you can always contact your GP for further advice. hope this helps, Take Care, Tommy's Midwives x

    • By anonymous (not verified) on 1 Aug 2017 - 14:48

      Had what i thought was my period on 27th july 2017, but very light compared to what they normally are. When should i take a pregnancy test?

    • By Midwife @Tommys on 2 Aug 2017 - 09:29

      Hi, it is worth waiting for a week or so before you do a pregnancy test so that the HCG levels in your urine have time to build up before you do a pregnancy test. Also, the best time to do a pregnancy test is first thing in the morning as the HCG levels have built up overnight and are more prevalent in the first void of urine in the morning.
      Please take good care of yourself

    • By Anonymous (not verified) on 30 Jul 2017 - 02:24

      I can't remember my last date of my period I think July 3-5 I have regular periods. I had unprotected sex on Morning of July 25 what's the possibility I could be pregnant (FYI I wasn't trying) I've had 2 miscarriage, one abortion

    • By Midwife @Tommys on 31 Jul 2017 - 12:47

      If you have had unprotected intercourse there is a possibility that you could become pregnant. You can obtain morning after contraception up to five days after you have sex. Contact your doctor or your pharmacist for advice.

    • By Anonymous (not verified) on 28 Jul 2017 - 11:02

      I expected my period in the 6th of July and I didn't see my period
      Had unprotected sex on the 8th of july
      Till now I haven't seen my period
      Can I be pregnant

    • By Midwife @Tommys on 28 Jul 2017 - 11:09

      If you have been having unprotected sex then there will be a chance that you could be pregnant especially if you are late with your period. I would suggest to do a pregnancy test to see if you are. If this test is negative and your period still does not come then to repeat the test in 5-7 days as it maybe that it is a little early and need time before the test can detect the hormone level. Take care x

    • By Anonymous (not verified) on 24 Jul 2017 - 02:03

      Hi i had my iud out on june 27th had sex same day untill my period on the 2 of july then had sex eveyday from the 7th to the 19th i took a pregnancy test 10 days before my next period but it came out negative just wanted to know if it's to early to know

    • By Midwife @Tommys on 24 Jul 2017 - 14:57

      Hello. If your last period was 2nd July it would be too soon to show up on a pregnancy test. Please remember though that for some women conception is not immediate and it can take several months before a pregnancy occurs. Best of luck

    • By Anonymous (not verified) on 11 Jul 2017 - 12:41

      I have been trying to conceive for almost a year now. I started using the ovulation tests but had to stop as it was disheartening every time I started my menstrual cycle. It made me feel so down to think I was doing the right things at the right time but no positive results. 2 years ago I had an ectopic pregnancy but they managed to save my fallipian tube. A couple of months ago I went to my doctor who did blood tests on two different occasions of my menstual cycle and they said there appeared to b no problems of me ovulating and all was well. I have also been taking Pre-vitamins that was recommended. I have been told to stop trying so hard and the past couple of months Iv tried to not think any more into it all but still no luck. Any suggestions as to what could help me please

    • By Midwife @Tommys on 13 Jul 2017 - 10:39

      Hi thank you for your comment. You are understandably feeling disheartened after nearly a year of trying to conceive but please feel reassured that over 80% of couples will get pregnant after 1-2 years of trying. This can be effected with age but you are doing everything right by taking your vitamins and being as healthy as you can. If you haven't conceived after a year then you are advised to see your GP who will be able to advice you further. It is easier said then done but try and relax as much as you can, take your time and hopefully this will help with conception. If you would like any further advice them please contact [email protected] or call us on 0800 0147 800 Monday to Friday 9am-5pm. Take care, Tommy's Midwives x

    • By Anonymous (not verified) on 3 Jul 2017 - 12:58

      I have 4 kids one abortion one lost in march this year I had 1 c section 3 normal deliveries I normal get pregnant easy fast ive been check over by doctors everythings looking good but I am tried ive trying nearly every night and only getting negatives test am getting tried and as a women and mum already I don't want nothing more I am 28 so thought It could be my age am not sure need advise ??????? help

    • By Midwife @Tommys on 3 Jul 2017 - 16:03

      The best advice is to look carefully at your lifestyle and ensure that you are in the best health possible. Ensure your weight is within the normal range and that you are exercising regularly. Remember to stop smoking and alcohol and to start taking folic acid and vitamin D.

    • By Anonymous (not verified) on 28 Jun 2017 - 12:24

      I have regular sex and have normal pregnancy before having normal periods but still not pregnant been trying 3 months now iam healthy eat well don't smoke or drink had a scan to check my body everything looks fine what else could it be???

    • By Midwife @Tommys on 29 Jun 2017 - 14:05

      Hi, Thank you for your comment. Sometimes it can take a little while to fall pregnant, it could be 6 months or even up to a year. You are doing everything right by looking after yourself. You have had a successful pregnancy before so there is nothing to suggest that this wont be the case second time round. You may want to try using ovulations kits if you haven't already, these will tell you when you are ovulating and the optimum time to have intercourse so you could conceive in your cycle. Hope this helps. Tommy's Midwives x

    • By hello (not verified) on 6 Jun 2017 - 11:50

      is it still possible for me to get pregnant after a miscarry in march I already have kids but we would love more ive been trying since april but feeling like my times up not getting any positives..../

    • By Midwife @Tommys on 6 Jun 2017 - 12:24

      Hi there.
      It might be a good idea to go to your GP to discuss this with them as they will know your full medical history, your obstetric history and be able to give you more detailed plan of care on how to move forwards and hopefully conceive another healthy pregnancy.
      If you need referral to gynaecology, your GP can also facilitate this for you too. Please do feel free to contact us again if you need any more advice! Take care.

    • By Midwife @Tommys on 6 Jun 2017 - 12:27

      Hi there.
      It might be a good idea to go to your GP to discuss this with them as they will know your full medical history, your obstetric history and be able to give you more detailed plan of care on how to move forwards and hopefully conceive another healthy pregnancy.
      If you need referral to gynaecology, your GP can also facilitate this for you too. Please do feel free to contact us again if you need any more advice! Take care.

    • By Anonymous (not verified) on 25 May 2017 - 13:59

      Hello my last month date is 29th March and I participate unprotected sex on 19th may can I get pregnant

    • By Midwife @Tommys on 25 May 2017 - 14:11

      Hi, if you have had unprotected sex and you haven't been using any form of contraception then yes it is possible to get pregnant.
      Best Wishes x

    • By destiny (not verified) on 29 Apr 2017 - 20:03

      how will i if am pregnant?

    • By Midwife @Tommys on 2 May 2017 - 14:20

      If you have been having unprotected sex and your period is late it is possible that you are pregnant so the next step would be to do a pregnancy test.

      Warm regards
      Anna- Tommy's Midwife

    • By Anonymous (not verified) on 18 May 2017 - 09:31

      I missed a period by 5 days it was due on the 3rd of may I a test clear blue easy that came back as a faint positive noq started to bleed on the Sunday for 3 days finished in went to the doctors done a urine test that come back negitive on the tuestay it wasn't enough blood to fill a pad the 2 following morning I had spotted now im testing negitive now I feeling like I'm pregnant as I've had a previous pregnancy, just so confused

    • By Midwife @Tommys on 18 May 2017 - 10:29

      It can be very confusing when you have had what you think is a faint positive test but then you bleed and afterward get negative pregnancy tests, it may be that you have had a very early miscarriage. If you continue to feel pregnant then it may be advisable for you to do another pregnancy test in a few days just to see if it is still negative. If you think that you may be pregnant then the GP can always do a blood test to check for the pregnancy hormone. Thank you for your comment and we wish you all the best.

    • By Anonymous (not verified) on 1 Jun 2016 - 06:11


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