Acoustic backscatter from a single target or organism is expressed as the intensity of an echo typically denoted as the backscattering cross-section (σbs, m2). Target strength (TS, dB re. 1 m2) is the logarithmic representation of σbs where: TS = 10 log10 (σbs). TS can be used to convert integrated (e.g. nautical area scattering coefficient, SA, dB re. 1(m2 nmi-2) or volumetric backscatter (e.g. Sv, dB re. 1 m-1) collected from fisheries acoustic surveys into units of number density, such as the volumetric density of a fish school (i.e. animals m-3). This parameter can also aid in classifying backscatter based on the multifrequency response of targets, such as separating likely echoes of large predatory fish from smaller prey. While there are several approaches for estimating TS, one common method is to apply physics-based models to predict theoretical TS that comprise exact and approximate solutions. The models provided in the acousticTS package can help provide TS estimates parameterized using broad statitsical distributions of inputs. This package is in a constant state of development with updates to the available model library, computational efficiency, and quality-of-life improvements.