NOW

Returns the computer system date and time. The value is updated when you recalculate the document or each time a cell value is modified.

This function is always recalculated whenever a recalculation occurs.

NOW()

NOW is a function without arguments.

=NOW()-A1 returns the difference between the date in A1 and now. Format the result as a number.

This function is part of the Open Document Format for Office Applications (OpenDocument) standard.

Date & Time Functions