When's the right time to have sex to get pregnant?

In the two days before you ovulate and on the day you ovulate. Ovulation usually happens about 14 days before your next period. Sperm can live up to five days but the egg only about a day, so having sex every one to two days through your fertile window gives you the best chance, without needing to time it to one exact day.

An ovulation tracker works out when your ovary is likely to release an egg each month, so you know your fertile days. This calculator does it from your last period and your cycle length. Tracking your periods and ovulation tests each month, for example in Grace, shows when you really ovulate.

Anyone trying to get pregnant, because sex in the days before ovulation gives you the best chance. It also helps if your periods are irregular, if you have PCOS or a thyroid condition, or if you're preparing for fertility treatment, since your doctor will ask about your cycle. On its own it isn't a reliable way to avoid pregnancy.

It's a good starting point if your cycles are regular. It assumes ovulation 14 days before your period, but in real cycles this varies by a few days. Logging your periods over a few months, or using ovulation test strips, gives a truer picture.

Clear, stretchy discharge like raw egg white, a slight rise in body temperature after ovulation, mild one-sided pain in the lower belly, tender breasts and a higher sex drive. Noting these each month shows you your own pattern.

It's unlikely but possible, because ovulation can come earlier or later than predicted. If you're trying, have sex every two to three days through the month. If you're avoiding pregnancy, don't rely on a calculator. Use contraception.

If your cycle length changes by more than a week from month to month, a calculator can be off by several days. Irregular cycles can be a sign of PCOS or a thyroid problem, so it's worth tracking them and talking to a gynaecologist.