According to SQL Server Help these are the ranges:
BIGINT: -2^63 (-9,223,372,036,854,775,808) to 2^63-1 (9,223,372,036,854,775,807)
INT: -2^31 (-2,147,483,648) to 2^31-1 (2,147,483,647)
SMALLINT: -2^15 (-32,768) to 2^15-1 (32,767)
For each of these data types...