Our ovulation calculator is easy to use and, no matter how well you know your cycle, it should be able to tell you which days of each month you’re ovulating (or at the very least, you’ll get an idea of the best time of month, fertility-wise, for you to be trying for a baby).


[ovulation_calculator widget_title="Ovulation calculator" date_picker_title="When was the first day of your last period?" menstrual_cycle_picker_title="What's the length of your menstrual cycle?" luteal_phase_picker_title="How long is your luteal phase?" button_title="Show my ovulation calculation" /]

How does MadeForMums Ovulation Calculator work?

For the ovulation calculator to work, as you'll see, we need some info from you – which you input into the calculator using the drop-down menu:

  • Firstly, input the exact day you started your last period.
  • Then, input how long your cycle usually lasts in days. Choose from anywhere between 20 and 40 days.

Your cycle starts on the day your period begins. It ends the day before your next period starts.

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Finally, if you know it, tell us how long your luteal phase is.

Don’t worry if you don’t: only those who’ve been TTC and very focussed on their cycle will have any idea what this is.

‘Luteal phase’ refers to the 2nd half of your cycle, which is when fertilisation and implantation can happen.

How do I make sense of the Ovulation Calculator’s findings?

Once you’ve done all that, a little calendar will pop up – that’s highlighted in pink and orange to show you the important days in your cycle.

The pink highlighted box is used to show the 1st day of your period, each month. Your most fertile days are highlighted in orange – these are the best days to have sex.

To see your most fertile day, look for the orange highlight with a brown box outlining it: that’s the day you’re due to ovulate.


The 2 days before your most fertile day, the day you’re due to ovulate, are also particularly fertile, so make note of those, too.

I’m not sure about my exact dates/cycle, but I’m pretty regular – can I use the MadeForMums Ovulation Calculator?

Yep, absolutely.

If you don’t have that exact info to hand, or you know your periods come and go like clockwork, then just tell us the date of your last period (or your best educated guess).

Leave the other two options as they are. We’ve automatically filled them with the averages – which is what we reckon most women will experience.

Cycles last, on average, 28 days. Luteal phases last, on average, 14 days.

For the best results, keep a close eye on your next period, the date it starts and how long there is until your next period starts. Then use the calculator again.

My cycle is irregular – can I use the Ovulation Calculator?

Yes, you’ll just need to make a few educated guesses in order to get the most accurate result.

(Keep in mind that, if you are very irregular, it’ll be difficult for the calculator to give you exact ovulation days.)

However, if you know your cycle usually lasts around 32 – 35 days, for example, you can pick a day between then.

Using that example, you’d interpret the results by looking at a couple of days on either side of the orange highlighted days.

You won’t have a longer fertile period, but you will have a roundabout idea of when you’ll be fertile – which is better than nothing!

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Tara BreathnachContent Editor and Social Media Producer

Tara is mum to 1 daughter, Bodhi Rae, and has worked as Content Editor and Social Media Producer at MadeForMums since 2015