Every day vs Everyday

Every day - here every is a determiner and day is a noun.
When you say every day you mean each day without exception.
For example: You have been late for school every day this week.

Everyday is an adjective.
When you say everyday you mean ordinary, unremarkable.
For example: My culture pages offer an insight into the everyday life of Britain.

Source : http://www.learnenglish.de