The fertile window is the few days in each cycle when pregnancy is possible. It is usually described as the five days before ovulation and the day of ovulation itself.
Sperm can survive in the body for up to about five days, while an egg can be fertilised for only about a day after ovulation. That is why the days before ovulation matter too.
What guidelines suggest
Because ovulation can be hard to pin down, NICE guidance suggests having sex every two to three days through the whole cycle rather than trying to time it exactly. Timing can add pressure, and regular sex covers the fertile window without it.
The day of ovulation varies from cycle to cycle and from person to person, even in regular cycles. This app shows only what you logged and never calculates or predicts a date.
Good to know
If you have questions about your own cycle, your doctor or gynaecologist can help you understand what fits you.