Finite-time stability (FTS) requires that the state of a system does not exceed a certain bound during a specified time interval for given bound on the initial state. The concept of FTS introduced exogenous inputs is called finite time boundedness (FTB). This paper gives necessary and sufficient conditions for FTB of linear time-varying continuous-time systems. The conditions are extensions of existing necessary and sufficient for FTS. The sufficient conditions for FTB are also given in terms of differential linear matrix inequalities, which can be relaxed by matrix sum of squares, univariate polynomials. Numerical examples show the solvability of the sufficient conditions.