An important problem that arises in the testing of software programs is that given piece of source code is reliable or not. Software reliability is an important segment of software quality. So software reliability must be quantified. Quantification refers to measurement. A number of software metrics and statistical reliability models have emerged during the past four decades but no model can solve the issue. In this paper, we conduct a survey on various software reliability metrics and models. Copyright © 2020 Inderscience Enterprises Ltd.