1
general::
Phrase(s): at (the) most
no more than the amount mentioned. • A: How far away is the beach? B: Ten miles at most. • At the most, there were only 15 people in the audience., Phrase(s): at most
Go to at best.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Also, at the most or at the outside. At the largest amount, the furthest limit; also, in the most extreme case. For example, She'll be finished in two weeks at the most, or It'll take two weeks at the outside, or At most the chef uses a tiny bit of pepper. The terms with most date from the 1300s; at the outside from the mid-1800s. Also see AT BEST.
American Heritage Idioms