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.

 

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Sources

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

 

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    Comments

    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 Joy (not verified) on 16 Jan 2019 - 17:03

      I finished my period on 23 then have unprotected sex n 29_1 can I be pregnant

    • By Midwife @Tommys on 17 Jan 2019 - 09:00

      Hi Joy.
      I presume you mean 23rd Dec was the end of your period and that 29th Dec you had unprotected sex. Any unprotected sex can cause a pregnancy. So it is really important that you protect yourself against pregnancy if you are not trying to conceive. Contraception will also protect you from sexually transmitted infections. Please take good care of yourself and do a pregnancy test if your next period is late. All the best, Tommy's Midwife

    • By chloe (not verified) on 14 Jan 2019 - 15:59

      hi midwife i saw my period on 27 dec 2018 den had sex on d 6th of january dis year just a round of it is it possible 4 me to get pregnant cos i nid it

    • By Midwife @Tommys on 16 Jan 2019 - 10:42

      Hi Chloe
      Any unprotected sexual intercourse can result in pregnancy. If your period is late, please do a pregnancy when your period is 7 days late for the most accurate result (whether it is positive or negative)
      Please see the link below for tips on when it is best to take a pregnancy test -
      https://www.tommys.org/pregnancy-information/planning-pregnancy/taking-pregnancy-test
      Take care, Tommy's Midwife

    • By rose (not verified) on 11 Jan 2019 - 11:05

      hi i had my period on 29-2 and i did unprotected sex 3 until now...can i be pregnant

    • By Midwife @Tommys on 11 Jan 2019 - 12:36

      Hi Rose,
      The only way of knowing if you are pregnant is to take a pregnancy test. If your next period does not come when due, then we would suggest taking a test. Taking a test earlier than this make result in a false negative result. If you think you may be pregnant or if you are trying for a baby, then we would advise you to be taking a daily folic acid supplement if you are not already.
      Best wishes,
      Tommy's midwife

    • By Tanya (not verified) on 10 Jan 2019 - 19:33

      November 30 period and again period December 23 as finish 27 Dec and unprotected sex January 1 so can get pregnant?

    • By Midwife @Tommys on 11 Jan 2019 - 12:19

      Dear Tanya,
      If you are having unprotected sex there is always a chance of pregnancy. The only way of knowing if you are pregnant is to take a pregnancy test. If your next period does not come when due, then we would suggest taking a test. Taking a test earlier than this make result in a false negative result. If you think you may be pregnant or if you are trying for a baby, then we would advise you to be taking a daily folic acid supplement if you are not already.
      Best wishes
      Tommy's mdiwife

    • By noeline (not verified) on 10 Jan 2019 - 13:39

      i had my periods on 28Dec ended on1Jan i've bad unprotected sex on 9Jan will i bepregnant?

    • By Midwife @Tommys on 10 Jan 2019 - 14:24

      If you have had unprotected sex, there is always a chance of pregnancy. According to the dates you have shared and if you have a regular 28 day cycle, then according to those dates you had sex during your fertile period in your cycle.
      If you think you maybe pregnant, it is best to start taking folic acid and a pregnancy test when your period is next due.

    • By Joy (not verified) on 22 Mar 2019 - 04:46

      If I have sex on the 18day of my cycle,will I conceive a baby boy? My cycle is 28day.

    • By Jane (not verified) on 3 Jan 2019 - 14:28

      This is the scenario. My boyfriend and I had sex around November 7 but he didn't ejaculate inside and he didn't even push it all the way in. My period arrived three weeks later around November 29 and ended around December 4. This December due to the holidays and school breaks, I started sleeping less at night and wake up late in the morning. My period for December didn't arrive and it's already January 3. Is it possible I'm pregnant?

    • By iboi ruth (not verified) on 2 Jan 2019 - 22:21

      i am 17 week pregnant i have sex through out my period day i had my period on 5 for August to10 and i also have sex everyday i want to kno when i got pregnant

    • By Lilian (not verified) on 2 Jan 2019 - 08:23

      hi, my period started on 11 december and had unprotected sex on 22, 23 and 24, would i become pregnant?

    • By Anonymous (not verified) on 2 Jan 2019 - 08:19

      hi, my period started on 11 december and had unprotected sex on 22, 23 and 24, would i become pregnant?

    • By Saydee (not verified) on 31 Dec 2018 - 08:43

      I had my period on the 7th of December and had unprotected sex on the 20th . I should go on my period on the 3rd of January.. can l ne pregnant

    • By Libbielove (not verified) on 31 Dec 2018 - 07:03

      Okay I usually come on the 20th or 21st of every month, here it is December I still have yet to come on. I’m now 11 days late. My bf and I had unprotected sex on December 16th could I have already missed my period ?? I am so confused

    • By Anonymous (not verified) on 29 Dec 2018 - 22:59

      please my menses was on December 27th what day will be my fertile day please help me

    • By Fausty (not verified) on 29 Dec 2018 - 22:00

      pls is it possible to be pregnant and still experience your the floor of blood every month

    • By Vishaka (not verified) on 28 Dec 2018 - 10:12

      I am 43 yrs. I started my periods on 3rd DEC and ended on 8th DEC. I had unprotected sex on 8th itself. My breasts started to hurt on 16th DEC. Please help me to know whether I am pregnant. I do not want to get pregnant at this age.

    • By kendasia goode (not verified) on 24 Dec 2018 - 02:15

      on december 20, which was on a thursday my boyfriend nutted inside of me but my period had just came on. what does that mean ?

    • By Catie (not verified) on 16 Dec 2018 - 22:41

      Hi I had unprotected sex 4 days prior to ovulation, is there a possibility that a pregnant can occur from this ?

    • By Midwife @Tommys on 19 Dec 2018 - 16:00

      Hi Catie
      Yes, you can become pregnant from unprotected intercourse, at any time during your cycle. So please use contraception if pregnancy is not planned. Take care - Tommy's Midwife

    • By Crystal (not verified) on 16 Dec 2018 - 15:50

      I've been having some issues with my period I went 10 months without one and got my first one from Nov 1 to Nov 25 but haven't had one since but I have also been having unprotected sex almost every other day before my period stopped I would bet it around the 1st of every month do u think I should take a test or see a Dr
      Thanks

    • By Midwife @Tommys on 19 Dec 2018 - 16:03

      Hi Crystal
      You need to go to your GP to discuss your history and be referred to a gynaecology clinic if you have not already done so. They need to investigate why your periods are so irregular and yes, may wish to do a pregnancy test whilst you are there. All the best. Tommy's Midwife

    • By Giana (not verified) on 14 Dec 2018 - 05:46

      I just want to know, my last period was nov 20 to 24, I had protected sex on Dec 10. I took combined pill Dec 11 because I got really scared. He finished inside me while in condom. When is the best time to take pregnancy test.

    • By Midwife @Tommys on 14 Dec 2018 - 15:18

      Hi Giana,
      If you used two types of contraception then it would be extremely unlikely that you are pregnant. If you wish to take a pregnancy test then it would be best to do this if your next period does not come when due, taking a test before this time would be too early and can result in a false negative.
      Best wishes
      Tommy's midwife

    • By Dolly (not verified) on 14 Dec 2018 - 02:53

      I had done sex on 1 November i experience my regular period on November ..but in month of December my date is on 9 th but it's not coming ..so I might be pregnant?

    • By Midwife @Tommys on 14 Dec 2018 - 15:13

      Hi Dolly,
      If you have had a full and regular period since the last time you had intercourse then it would be very unlikely that you are pregnant. If your period does not come in the next few days then do a pregnancy test to be sure.
      Best wishes
      Tommy's midwife

    • By AmberBanks (not verified) on 12 Dec 2018 - 16:58

      I had a period on June 16-20...i have regular cycles..i always have 4-5 days of a period...i had intercourse on the 23rd and the 1st of July...I believe i ovulated on the 30th or the 1st of July...I recevied another period on the 15th of July which came on time and ended on the 18th i had intercourse on the 14th of July and the 19th and also the 25th of July...i ovulated on the 28 or the 29th of July... I am now 21 weeks nd 3 days of today(12/12/18) with a due date of April 21st 2019...which sexual incounter gave me this due date?

    • By Midwife @Tommys on 14 Dec 2018 - 15:11

      Hi,
      I am afraid I would be unable to say exactly when you conceived this pregnancy, however on the dates that you have provided, it was most likely in the last couple of weeks of July.
      Best wishes
      Tommy's midwife

    • 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 Tonia (not verified) on 20 Jan 2019 - 09:27

      Throughout last year i do see my period every on the 15th... but dis year it begins on the 12 jan nd last for 4day on the 15th wen wil my ovulation begin?

    • 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

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