When do boys become Mr rather then Master?

[BrightBlueHue]

Helping DS (16) to complete his college application.

Title HAS to be filled in.

Question is, when do boys become a Mr? 16 or 18? There seems to be a mixed response online.

Posting here for traffic!

In many cases, titles are asked for when it’s completely unnecessary. The only reason they are needed is if the organisation is going to write to you. As women can go through their whole lives being ‘Miss’, that is a valid option. As organisations don’t normally write to little boys, but rather their parent or guardian, master does sound old-fashioned. So OP, it’s definitely Mr!