ReliabilityBench is a free engineering workbench for reliability and maintenance professionals. It provides 29 calculators for MTBF, MTTR, availability, OEE, system reliability, Weibull analysis, downtime cost, maintenance ROI, repair-versus-replace decisions, and MRO spare-parts planning. Each tool includes formulas, input guidance, result interpretation, assumptions, limitations, and related technical references. No signup is required.