Hello, if your fingertip touches the sneakers, it means that the shoes are a little too small for you. If you wear size 38 in summer shoes, it may be because they are wider or more flexible. The Adidas Runfalcon model is generally a normal fit. In this case: 38.5 provides a little more comfort, but it may not completely solve the problem of not touching the fingertip. Size 39 may be ideal for you, it will provide finger space and your feet will be comfortable. 39.5 can create a lot of space standing, which can cause the foot to slip inside. Therefore, the most correct choice will be number 39. If you need me to help with something different, as KoraySpor, we are always by your side.