If you are trying for a baby, to increase your chances of conceiving, it helps to know when you are at your most fertile, and when is the best time to have sex. 

Your fertile window 

Conception is possible during the ‘fertile window’ – the five days leading up to, plus the day of ovulation. The chance of you becoming pregnant is greatest if you have sex during the two days leading up to or on the day of ovulation.  

Ovulation happens about 14 days before your period starts.

How you know you’re ovulating

To work out your ovulation day, you need to know how many days there are in your menstrual cycle. 

Each woman is different, so to calculate your cycle, count from the first day of your period to the day before your next period. 

This chart shows the most fertile days for some menstrual cycles. You can also use this handy fertility calculator on the Your Fertility website to calculate your most fertile period. 

Fertility chart

Length of cycle   Ovulation day   Most fertile period 
35 days  Around day 21   Days 19, 20 and 21
32 days Around day 18  Days 16, 17 to 18
28 days Around day 14  Days 12, 13 and 14
24 days Around day 10  Days 8, 9 and 10
21 days Around day 7   Days 5, 6 and 7

Be in tune with your body

Your body changes at different stages of your cycle. A few days before ovulation the vaginal mucus changes and becomes clear and slippery – a bit like egg white and perfect for

sperm to swim along! When you notice this change, it’s time for sex.  

Get technology involved

An ovulation predictor kit, available at any pharmacy or supermarket, can be useful. It’s a simple urine test you can use a few days before you ovulate. A positive result means you are likely to ovulate within the next 24 to 36 hours, which is when you should be having sex.

If it’s all too hard

If this all seems too much of a bother, or if your cycle isn’t regular, just make sure you have sex every two to three days. This will give you the best chance of conceiving. 

So, get yourself ready for the next fertile window and good luck!

For more information about fertility and ways to increase your chances of having a baby, visit Your Fertility

Your Fertility is brought to you by the Fertility Coalition: the Victorian Assisted Reproductive Treatment Authority (VARTA), Andrology Australia, Jean Hailes Research Unit, and the Robinson Research Institute.

Your Fertility is a national public education program funded by the Commonwealth Department of Health and the Victorian Department of Health & Human Services.

Victorian Assisted Reproductive Treatment Authority


Victorian Assisted Reproductive Treatment Authority

The Victorian Assisted Reproductive Treatment Authority (VARTA) is a statutory authority funded by the Victorian Department of Health and Human Services. VARTA provides independent information and support for individuals, couples and health professionals on fertility and issues related to assisted reproductive treatment. This includes IVF, surrogacy and donor-conception.