The Berkeley Advanced Reconstruction Toolbox (BART) toolbox is a free and open-source image-reconstruction framework for Computational Magnetic Resonance Imaging developed by the research groups of Martin Uecker (Göttingen University) and Michael Lustig (UC Berkeley). It consists of a programming library and a toolbox of command-line programs. The library provides common operations on multi-dimensional arrays, Fourier and wavelet transforms, as well as generic implementations of iterative optimization algorithms. The command-line tools provide direct access to basic operations on multi-dimensional arrays as well as efficient implementations of many calibration and reconstruction algorithms for parallel imaging and compressed sensing.