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Ovulation Calculator

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Trying to conceive (TTC)? Work out when you're most fertile and when is the best time to get pregnant, to increase your chances of getting pregnant with our easy-to-use ovulation calculator.

All you need to do is put in the first day of your last period. 

Then we need to know the average length of your menstrual cycle so we can calculate the window of time when you're most fertile. While the average cycle lasts 28 days, anything from 22 to 36 days is perfectly normal, so pop your number in and press 'submit'.

What to read next:

How soon after coming off the pill can you get pregnant?
10 trying to conceive tips the experts want you to know
6 Factors that increase your chance of having twins or multiples

What does the calculator mean and when are your most fertile days?

The asterix show the day you're ovulating. And all those days that are ticked? That's when you're at your most fertile, so this is the best time to get pregnant.

The days shaded blue are the days your period is due – and a great tally for working out when it's time to take a pregnancy test.

Boost your chance of conceiving

Now you know when you're most fertile, make the ovulation calculator results work for you and figure out what you need to do to boost your chances of conceiving no matter where you are in your menstrual cycle - and to find out when is the best time to get pregnant in your cycle.

Your period’s due - week one

If you've got your period (when you were really hoping it wouldn't happen) stay positive. Just think, if you do conceive this month, this will be considered week one of your pregnancy.

But if you think there could be some bad habits that are stopping you getting pregnant, this is a great week to make those healthy resolutions, including taking folic acid, and sticking to them.

And if that period isn't showing up? While it's never great to obsess about the early signs of pregnancy and when to take a pregnancy test, being aware of them is a good idea.

You’re almost in your most fertile week - week two

Focusing on what you both eat in this week will help ensure you're on top form as you come into your most fertile time. Find out the foods that boost his sperm count and help your fertility.

Remember, that TTC sex shouldn't just be about that most fertile week. And if your heart's set on trying to get pregnant with a girl, there is a theory that conceiving before your fertile week could help.

You’re in your most fertile week - week three

You're most fertile so now's the perfect time to enjoy plenty of baby making sex - this is the best time to get pregnant.

And while, yes, you really want to get pregnant right now, remember you want a baby with him, so it's worth making sure TTC doesn't take over your relationship.

You’re just out of your most fertile week - week four

While trying to conceive is top of your agenda right now, keep in mind that your life isn't all about getting pregnant – and that you're not the only couple going through this. The 10 things you only know if you're trying to conceive should ring true.

That said, if you're needing an excuse to have a health overhaul, this could increase your chances of conceiving, too. If you've decided to take your basal temperature to use alongside the ovulation calculator, now's the time when you should be seeing a change.

For more information and support, visit our dedicated Trying To Conceive channel.


  • Victoria - 27/09/2015 07:13

    Please help i usually see my periods twice a month what can i do

  • bella - 20/10/2015 10:24

    Pls I noticed dis spotting always instead of my normal mensuration, since I stopped breastfeeding my second baby, wat could be the cause, and can it prevent me from getting pregnant?

  • yourlordac - 27/10/2015 23:10

    I need some help right now. My partner and I had unprotected sex on the 7th, 8th, and 13th October. I usually have period cramps a week before I am due on, but I've had small cramps on one side of my body, which is odd for me. My period arrives around the 27th. I've also been feeling extremely tired. I've taken two pregnancy tests, but they've both said negative. Is it too early?

  • chigold - 30/10/2015 11:39

    tanx for d information

  • Genevieve siame - 04/11/2015 14:32

    Please me n my partner have been try to have a baby for the past 3years now but no avail, we did some txd n we were told everything is fine, pls help us

  • Rinibeth - 10/11/2015 09:34

    Hello please i have been on pregnacare conception and folic acid over four months, I had my period between 3rd October to 6th october then again on 29th October to 1st November. I had sex from 29th October to 4th November. Is it possible I'll get pregnant?

  • Crivers - 03/01/2016 08:59

    Please help. I had my period on the 20 of November. It ended on the 25. Usually I have about 28 to 31 day between my periods. I had sex on the 27 of November, two days after my period ended, but I haven't had sex since. We used protection but I am not on the pill. Please help. What is he chance that I could be pregnant? I am 16 days late for my period and I am freaking out.

    • Mother&Baby - 04/01/2016 17:17

      Hi, the best advice would be to do a pregnancy test, and go to see your doctor.

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