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.


Follow Tommy's PregnancyHub on Instagram


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


Hide details

Your stories of planning for pregnancy

  • Couple Amanda and Judd with daughter Shelbie


    Importance of planning for pregnancy

    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.

  • 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?

    Yes No


    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 Susan Efona (not verified) on 19 Jun 2019 - 04:57

      I had just finished my period on 30 may and I had sex on, may 31, June 3, and june 10, can i get pregnant ?

    • By Anonymous (not verified) on 23 Jun 2019 - 22:16


    • By Iris (not verified) on 18 Jun 2019 - 07:31

      My period start this june 11,2019,, and its finished this june15,2019..so what day im going to ovulation and my fertile window start? I want to be become,,.pregnant. Please help ask.. Please help me the maximum date were we have sex..

    • By Anonymous (not verified) on 14 Jun 2019 - 13:51

      I had my periods on 3rd to 5th June 2019 I had sex on 12th June can I get pregnant

    • By Elizabeth peter. (not verified) on 10 Jun 2019 - 20:34

      I have miscarriage last year September. But not able to get pregnant again what can I do?since then I have been having irregular period and have done different scan but fine nothing.please I need help

    • By Anonymous (not verified) on 25 Jun 2019 - 17:52

      Hi i am in the exact same boat I had a misscarage on the 4th sep a should been 17 weeks but everything stopped at 9 weeks... I still have not fell pregnant either. Am just taking each day as it comes.

    • By vida gyasua (not verified) on 5 Jun 2019 - 08:35

      i had my menses on 14 may,and had unprotected sex on 31 may,do i have the chance of getting pregnant.

    • By Nikia (not verified) on 30 May 2019 - 23:54

      My last period was on the 28 of April finish the 2 of may....my period is suppose to come bavk the 28 a may but it doesn't... I had unprotected sex on the 18 and 19 and then on the 24 could it possible be that I am pregnant because I miss my may period...and my breast r so tender?????

    • By Val (not verified) on 31 Jul 2019 - 21:39

      Hi. You might be. Did you founf out yet?

    • By faith (not verified) on 29 May 2019 - 23:27

      period started 21, ended 24, had sex 24, to

    • By Anonymouse (not verified) on 16 May 2019 - 20:41

      My last periods was on the 24 April 2019 to 27 April 2019.
      Then i had sex the following days (28-01 May)
      Can i get pregnant?... nd i also had sex yesterday and stil waiting for my periods?

    • By Joy (not verified) on 16 May 2019 - 00:29

      I had sex on the 13 of april unprotected then had started cycle on April 17th then had sex on April 17th as well . I've had symptoms of pregnancy .

    • By gerremech (not verified) on 15 May 2019 - 11:47

      I had unprotected sex on the 13 May then went mensuration on the 4 may to 9 may then the next month do I get pregnant on next month?

    • By Want to know (not verified) on 14 May 2019 - 14:21

      I had my periods on 16 of April it end on 20 of April and I had sex on 22,23,27 and after that I had light bleeding for a few hours on the 29 of April I have a cycle of 28 days can I be pregnant

    • By lilian George (not verified) on 9 May 2019 - 13:29

      I want a twins baby boy

    • By Sebongile (not verified) on 3 May 2019 - 01:29

      I had unprotected sex on the 10 and 11th Feb then went mensuration on the 12 to 16th Feb then the next month I missed my periods so when did I conceive?

    • By Kim (not verified) on 2 May 2019 - 22:33

      Your ovulation app got me pregnant all other apps were days off my actual ovulation I'm due 14th Jan thank you

    • By By anonymous (not verified) on 30 Apr 2019 - 13:59

      I had my period on 16th April and I started having sex from the 4th day till 27th April every day can I get pregnant

    • By Sajitha (not verified) on 30 Apr 2019 - 07:27

      Lmp 7 April last sexual contact in April 26 how can possible to conceive please reply immediately

    • By Jennifer (not verified) on 29 Apr 2019 - 20:09

      My husband doesn’t stay in the country and I had my last period on the 22/3/19and it ended on the 25/03/19. Then he arrived on the 3/4/19 since then we have been having sex for the past two weeks till 19/4/19and now Am yet to see my period which I have missed for 8days and I have done HCG pregnancy test it was negative
      Pls What should I do best

    • By Cynthia (not verified) on 14 May 2019 - 12:26

      Hi...i think you will need to go for a scan.
      Also are you on any FP plan?

    • By Jk (not verified) on 24 Apr 2019 - 14:24

      I got my periods on the 19th and ended on the 21 April 2019 on the 20th I had unprotected sex are there chances that I can get pregnant?

    • By Anonymous (not verified) on 4 Apr 2019 - 15:10

      I had my period on the 21st of March and lasted for 5days and I began having sex with my husband on the 25th March till April 3th have been feeling as to vomit since April 1st and am expecting my period on the 15th April could I already be pregnant and can I go in for a pregnancy test now

    • By Midwife @Tommys on 4 Apr 2019 - 15:12

      Pregnancy tests work by detecting one of the key early signs of pregnancy: a hormone called human chorionic gonadotrophin (hCG). This hormone is only made when a woman is pregnant.

      Traces of hCG can be found in the urine from three to four days after implantation, but the concentration needs to continue to build up to a level at which the test can detect it and give a positive result. The best time to take a pregnancy test is from the day that the period is missed.

    • By Debby (not verified) on 31 Mar 2019 - 08:42

      Hi i had my period on the 21/03/09 to 25/03/09.then i had unprotected sex on the 29/03/09 .I haven't taken any contraceptive pills. But is it possible for me to get pregnant? Please reply.

    • By Kimberly S Thompson (not verified) on 31 Mar 2019 - 03:23

      I had miscarriage on march 21st 2019, when would be best to try again?

    • By LIL (not verified) on 24 Apr 2019 - 00:33

      I had my miscarriage on the 22nd of March. I started 2 weeks after my miscarriage. I started trying on the 31st of March I do not want to waste any time.

    • By lisa (not verified) on 27 Mar 2019 - 03:36

      the last time I had sex was 6 months ago and it was unprotected. recently I have missed 2 periods and have had stomach pains that are different than a regular belly ache, it's not possible to be pregnant right?

    • By Anonymous (not verified) on 22 May 2019 - 01:45

      Stomach pains are not a symptom of pregnancy. Missed period, tender breasts, and nausea with or without vomiting are symptoms of pregnancy

    • By Suma (not verified) on 26 Mar 2019 - 07:14

      I had sex on the day of period it's on 8 and in the mrng i had sex and after noon I got period and ithe bledding was less after doing sex

    • By asha (not verified) on 23 Mar 2019 - 07:47

      my period date after 29th day only one sex i am conceive or not

    • By Nessa (not verified) on 22 Mar 2019 - 03:57

      Hi, I stopped my pills a few days into my second pack. I know I ovulated during that time frame. Well at least all my ovulation symptoms were there. How would I calculate my due date since technically my ovulation was unexpected.

    • By Cynthia (not verified) on 21 Mar 2019 - 15:18

      Pls ma I saw my period on 17feb I haven't I heard unprotected sex throughout pls am I pregnant

    • By Midwife @Tommys on 21 Mar 2019 - 16:46

      Hi - Thank you for your message.
      If your period is delayed and there is a chance you are pregnant it is important you carry out a pregnancy test.

    • By Ajoka blessing (not verified) on 13 Mar 2019 - 06:44

      pls I was a Virginia but then I decided to have sex but it was a protect sex I did it about two times and now am just been worried, thinking if I might see my period or not because I saw my last period on the 23rd of Feb. and now am in march 13 when am I suppose to see my next period please

    • By Sthembiso (not verified) on 22 Feb 2019 - 12:42

      Iv been going to periods twice a month but this month I didn't.I started having pains around 1am thn started mensturationg around to 4am today on the 22 of February.And its paining and the blood is too little.the pains sound like a from the womb.wt could be the problem coz I'm not using any pills or neddle.?

    • By Mary (not verified) on 21 Feb 2019 - 07:17

      I had sex on the 9th&10th day of my cycle....i ovulated on the 13th day of my cycle...could i be pregnant

    • By Esther (not verified) on 14 Feb 2019 - 19:30

      Pls I had my period on 18/01/19 and ended on 23/01/19 but had unprotected sex on 07/02/19 after that I took a contraceptive and had another one on 08/02/19 and also took a contraceptive is it possible to get pregnant. I suppose to had my period today but didn't see it. Please help me out, am feeling slight pains in my abdomen.

    • By Sanctity (not verified) on 13 May 2019 - 11:09

      I have the same issue with her,I had my last period on 11/04 /2019 and ended on 15/04 /2019. I had unprotected sex on 30/04 /2019 after that I took a contraceptive, is it possible I get pregnant? I suppose to have my next period on 10/05/2019

    • By Manuela (not verified) on 12 Feb 2019 - 11:47

      My last of menstrual was the 11th till the 14th November. I had sex on the 23rd of November. I did a pregnancy test (3). And all came out a bit lighter than there other line.

    • By maryam (not verified) on 12 Feb 2019 - 11:37

      I had a baby last year Aug22, had my first menstrual period on the 10th of January, had sex immediately after my period (6thday) and 2weeks ago but I'm yet to see my next menstrual period.. hope I'm OK?

    • By Anonymous (not verified) on 5 Feb 2019 - 13:31

      I got my periods on 23rd December 2018 and then took and emergency pill on 27th December and then got periods on 4th January and I been use protection condoms and not its 6th of feburary 2019 I still didn't get my periods what to do I'm so worried should I take pregnancy test ?

    • By brenda (not verified) on 25 Jan 2019 - 03:20

      last time I had my period was November 28 to December 3rd. I am an irregular, I didn't got my period on December I had unprotected sex 2 days ago. according to my chart I should of got my period yesterday. Does this means I'm pregnant?

    • By Gm239 (not verified) on 24 Jan 2019 - 08:59

      So my last period was December 14th which I was supposed to get it probably January 11th but I had sex on Unprotected sex on January 3rd I tested already a few days ago and it was negative still haven't gotten my period does it mean I'm not pregnant

    • By Midwife @Tommys on 24 Jan 2019 - 11:30

      HI - Thank you for your message.
      If you have had a negative pregnancy test and your period is still delayed after having had unprotected sex, you should wait a few more days and re-test. Following that you should visit your GP for advice.

    • By Kat (not verified) on 20 Jan 2019 - 06:47

      Last time, I had written about being concerned. Now, I am not sure of pregnancy. I did get treated for bacterial infection and yeast. Lmp 12/22/2018. Unprotected sex duri g fertility period on dec.29, 2018. My period tracker miscalculated. Spotting or light bleeding on jan.14 and 15, 2019. Stop suddenly and very very light brown. Period suppose to start today jan.19, 2019. Nothing as yet. Not sure if pregnancy or what. Yes, I have very bad mood swings, tired, food crack gr8, but nothing I would think of pregnancy. Have to schedule well woman exam next month in February 2019. Will I know then .

    • By Larry (not verified) on 18 Jan 2019 - 17:33

      I had miscarriage on September 2018 and since then have been willing to have another pregnant but all my effort was Zero what can I do because my husband family have been pressurise me.

    • By Midwife @Tommys on 21 Jan 2019 - 16:50

      Hi Larry
      I would advise that you try for your next baby when you feel ready to do so, not because of family pressure
      The following links have helpful information and advice for you
      We generally advise that if you have still not conceived after a year of trying then you should contact your GP for referral for further tests to find out if there is a cause for this.
      Take Care
      Tommy's Midwife

    • By Faido (not verified) on 23 Mar 2019 - 11:05

      Am sorry bcoz of that madam.First is good to give your body time atleast six month for it to heal and also hormones to balance.Thankyou

    • 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

    • Pages

    Add new comment