How it is worked out
The page takes the time on your own device and measures how far it is through the year, the quarter, the month, the week and the day. A year is 365 days, or 366 in a leap year, so each day is about 0.27 percent of it.
Everything is measured on your clock, not a server's. Someone in Sydney is further through the year than someone in Los Angeles for most of a day, and each of them sees their own number.