Women of childbearing age ovulate every month. This means that one of the two ovaries releases an egg after it has matured in the ovaries. When the tiny egg, which measures approximately 0.15 cm, is released, it becomes trapped in the woman's fallopian tube, and now begins a journey of an average of 5 days before it reaches the uterus. There is now a chance of pregnancy if the egg meets a spermcell within 24 hours after ovulation which succeeds in penetrating the egg and fertilizing it. It is therefore a very short period during each cycle when a woman has a chance of becoming pregnant. If you want to increase the chance of pregnancy, it can therefore make very good sense to keep a close eye on ovulation.

How long does ovulation last? 

It takes approximately one day from the time the egg has been released from the ovary until it is no longer possible to be fertilized. But still, it is said that a woman with a normal cycle has 5-6 fertile days. This is because sperm can live for up to 6 days inside the woman after intercourse. So, if you have intercourse 5 days before ovulation or within the first 24 hours after ovulation, there will be a chance that a sperm cell can fertilize the egg. 

When do you ovulate? 

A woman's cycle lasts an average of 28 days. This means that 28 days pass from the first day of menstruation to the last day before the next period. However, a cycle of anywhere between 23 days to 35 days is normal. In a 28-day cycle, ovulation will usually occur on day 14. Use the chart here if you want to see when you are expected to ovulate or when you should start testing if you want to use ovulation tests. To see when you ovulate, you can also use the temperature method, which you can read more about here: What is the temperature method BBT and how does it work? – Gravidtid

If you want to see our large selection of ovulation tests, you can see it here: Ægløsningstests – Gravidtid You can find our thermometers here: Termometre – Gravidtid

Cycle length

Expected ovulation on this number of days following last menstrual cycles first day

Start testing with ovulation tests as many days after the first day of your last period

21

7

5

22

8

6

23

9

7

24

10

8

25

11

9

26

12

10

27

13

11

28

14

12

29

15

13

30

16

14

31

17

15

32

18

16

33

19

17

34

20

18

35

21

19

36

22

20

37

23

21

38

24

22

39

25

23

40

26

24

Source: Sundhed.dk, Herlev Hospital, Netdoktor