up to

down to, up to

1. When referring to people and their actions, down to suggests obligation or responsibility whereas up to suggests opportunity. If you say It is up to them you imply that they have a choice about how to act, whereas if you say It is down to them you imply that they are responsible for acting or having acted in some way. Examples:

• The boom in Gucci and Pucci and…Lacoste ‘names’ on clothes, bags and other ornamentation is all down to the Yuppies —Sunday Telegraph, 1985

• Poor ethos in a school may be down to one person, good ethos is down to everyone —Times Educational Supplement, 1999.

The origin of this use is possibly connected with the phrase come (or be put) down to, which has a similar meaning:

• My remarks…should be put down to my own lack of sympathy with the scientistic vision which Thomas upholds —Times Literary Supplement, 1980

• One of the biggest fears is not being believed. It nearly always comes down to one person's word against another's —Sunday Mercury, 1998.

2. Down to and up to are used interchangeably in the meaning ‘until’ (up to the 19th century or down to the 19th century), except that the viewpoint is slightly different, up to being essentially forward-looking and down to retrospective.