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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    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 Arooj (not verified) on 30 Jan 2020 - 13:03

      I've got a baby boy. He is 2 years old. I'm trying for another baby but I don't get pregnant. I'm trying for four months( Actually I took the pill just 3 months to prevent pregnancy) I think that I don't get pregnant because of this

    • By victory (not verified) on 28 Jan 2020 - 04:01

      I stared my period today when I am supposed to ovluate to get pregnant

    • By victory (not verified) on 28 Jan 2020 - 03:57

      I started my period 28 when I am supposed to ovulate to get pregnant

    • By Liza valks (not verified) on 25 Jan 2020 - 20:58

      My first period is 19 October I have a chance to get a pregnant first intercourse is 30 October to my partner for the last 11 months months.
      And I know this Jan 25 I'm pregnant but I don't know how to calculate of this .I hope you answer me

    • By Mosima (not verified) on 24 Jan 2020 - 21:58

      The first day of my last period was on the 25th Dec 2019 and I had sex on 31 Dec 2019, now my period are late, am I pregnant?

    • By Beatrice (not verified) on 21 Jan 2020 - 08:31

      I saw my period on the 16 January and complete it on d 20, when are my ovaries going to be ready

    • By Rosyli Palaubsanon (not verified) on 21 Jan 2020 - 18:18

      I saw my period,last dec 28,2019.but it should be dec.16...my boyfriend and i making love last dec.13...is it possible to become pregnant?that i saw my blood last dec.28 2019

    • By Anonymous (not verified) on 17 Feb 2020 - 23:57

      Use the ovulation calculator it gives an idea on when to try for a baby

    • By Faith (not verified) on 16 Jan 2020 - 15:21

      My period come on second of this month please when is ovulation

    • By Benny (not verified) on 11 Jan 2020 - 13:22

      I had unprotected sex on the 24th day of my cycle after evacuating, I am supposed to see my period yesterday which is the 28th day of my cycle but not forthcoming, I am possibly pregnant?

    • By an Juliet (not verified) on 7 Jan 2020 - 23:06

      I saw my period on 4 and finish on 8 plz when we I see my ovulation

    • By Micheal chioma (not verified) on 7 Jan 2020 - 22:20

      I saw my period on the 28th of Dec to 1st Jan 2020 when am i expecting my ovulation

    • By louis (not verified) on 6 Jan 2020 - 12:08

      my period is not regular. it's sometimes skips a month, sometimes two months, sometimes three months. with this situation, how do I calculate my ovulation and increase my chances of getting pregnant

    • By bulelwa (not verified) on 26 Jan 2020 - 19:28

      My period come and go and I've been trying to have a baby now im taking pregnancy supplements its about a month now

    • By Oluwa (not verified) on 4 Jan 2020 - 02:01

      I finished my period on the 12th of December 2019.. I had Sex on 22th of the same month...

    • By Blessing (not verified) on 29 Dec 2019 - 16:51

      started menstruation on 13 December, had sex on 28 night could I be pregnant?

    • By blessing (not verified) on 4 Jan 2020 - 10:31

      if I see my mensuration on 2 January 2020 than how many days will it take for my ovulation to come out

    • By Rhoda (not verified) on 28 Dec 2019 - 23:52

      Am confused,the ovulation is how many days?
      and it is after menstruation or is the 10th day to 15th day?

    • By Ems (not verified) on 26 Dec 2019 - 03:20

      I have sex in 26 my last mens is dec 5 can i get pergnant before my nxt..txn

    • By Pat (not verified) on 18 Dec 2019 - 15:35

      I saw my period on the 8 Dec and completed it on d 11.when are my ovaries going to be ready

    • By Suz (not verified) on 19 Dec 2019 - 09:47

      I had my periods on December 6 and completed them on d 10th wen will I ovulate.

    • By Evelyn (not verified) on 27 Dec 2019 - 12:08

      I want to know my next fertile days

    • By Srabani DUTTA (not verified) on 5 Jan 2020 - 14:12

      My up coming ovaculation date I want to know

    • By Obi doris (not verified) on 22 Jan 2020 - 19:35


    • By Priscillia (not verified) on 17 Dec 2019 - 20:46

      My last period was july4, and i had sex on july 10 with my ex another one on july14 with my bf am pregnant dont no the owner.

    • By Sophie (not verified) on 10 Jan 2020 - 13:40

      The only way you will know the man responsible for that pregnancy is when you give birth & get a DNA test.

    • By Bertha (not verified) on 13 Dec 2019 - 06:40

      I Started Bleeding At 5th Dec And I Completed At 11th Dec So When Are My Overias Going To Be Ready?

    • By Esther King (not verified) on 20 Dec 2019 - 03:54

      Our cycles are the same 17 to 23rd

    • By Dennis Amarachi (not verified) on 11 Dec 2019 - 17:18

      Start period on 4 December ends 8 December when am I ovulating

    • By Lawalson Taiwo (not verified) on 18 Dec 2019 - 13:09

      I start my period on 22nd and finish it 26th day, what date is my ovulation .

    • By Rhoda (not verified) on 28 Dec 2019 - 23:33

      I prefer natural family planning

    • By Cole (not verified) on 9 Dec 2019 - 15:48

      Just started my menstruation today (4days), pls how do I calculate my ovulation and my chance of getting pregnant

    • By Pat (not verified) on 22 Dec 2019 - 09:47

      I had a spot today when will I ovulate

    • By Hally (not verified) on 22 Nov 2019 - 11:34

      I had my period on 2nd of November and I had unprotected sex on 10th of November a day to my ovulation what is the tendency, pls I need an urgent reply.......

    • By Diva (not verified) on 20 Nov 2019 - 23:43

      My last period was on October 16. 2019, I had unprotected sex on 8th 2019 November and now my period is late. Can I be pregnant. Please help

    • By Ayoade adenike (not verified) on 27 Oct 2019 - 20:42

      I started my menstruation 14th October and ends 20th October wen is my ovulation date

    • By Meena (not verified) on 15 Oct 2019 - 03:37

      My mensturation sep 17 and I have Intercourse in sep 5, so I got pregnancy is possible or not, and I have 2month baby and give breast feeding please help me

    • By Oyise hope (not verified) on 1 Oct 2019 - 18:51

      I saw my period last month 24 and ended 27

    • By Olayemi (not verified) on 8 Oct 2019 - 14:59

      I did my 1st period on 3rd of last month and another 26th of last month too when was my ovulation time pls help me

    • By Michelle (not verified) on 16 Oct 2019 - 18:59

      If you have a regular 26 day cycle then you could have ovulated between the 10th - 15th of the month.

    • By lulu (not verified) on 27 Sep 2019 - 14:56

      I saw my period last month August 27 is it normal I see on 27 September

    • By caitlyn (not verified) on 7 Nov 2019 - 15:14

      yes. it is a 30 days cycle

    • By Ruby (not verified) on 22 Sep 2019 - 12:02

      I can sex after periods 7 days is it the any chance of pregnancy

    • By Crystal (not verified) on 30 Sep 2019 - 14:58

      I had sex with my husband after my 7 Day of my menstrual cycle is it a chance I can't get pregnant

    • By Olivia (not verified) on 15 Sep 2019 - 06:41

      My menstruation started today 15 September 2019, i want to know my days, i want to works towards getting pregnant immediately and my ovulation day, i need twins thanks ..

    • By Sirisha K (not verified) on 20 Sep 2019 - 08:36

      Why am getting stomach pain and abdominal pain during ovulation days

    • By Kanya (not verified) on 1 Oct 2019 - 14:15

      I had test, the result says I'm 3+ now I'm confused cause, I think I got pregnant on 6th September

    • By Lydia (not verified) on 17 Oct 2019 - 21:03

      I will appreciate

    • By Angel (not verified) on 14 Sep 2019 - 19:47

      I had my period on d 12 August 19.I had sex with my bf 5 datz after....ad later had sex with my ex 10 later.now am pregnant Hw do I knw who is d father

    • By Michelle ross (not verified) on 10 Sep 2019 - 13:11

      i started my period on the 23rd of august and finished periods on 27th august has unproted.sex on the 1st september is it possible i could be pregnant i am getting cramping in my lower stomach

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