When a reliability test ends in zero units having failed, traditional reliability calculations suggest that the estimated failure rate is also zero, assuming an exponential distribution. However, this is not a realistic estimate of the failure rate, as it does not take into account the number of units on test. In such cases, a reasonable approach is to select a failure rate that makes the likelihood of observing zero failures equal to 50%. In other words, we select a failure rate that carries with it a high probability of observing zero failures for a given reliability test'. In this paper we review this methodology and demonstrate how it has been implemented at Advanced Micro Devices (AMD) through a user friendly EXCEL based software application. Customized software tools such as this have led to increased awareness, productivity, and accuracy in reliability calculations at AMD.