Kalibr is a software suite for multi-camera calibration and visual-inertial parameter estimation. It provides a mathematical framework for determining intrinsic and extrinsic parameters across multiple cameras and calculating the spatio-temporal offsets between cameras and inertial measurement units. The project features a non-linear least-squares optimizer to minimize reprojection and inertial errors. It includes specialized tools for rolling-shutter camera calibration to estimate projection and distortion parameters for sensors that capture images row-by-row. The system covers a broad rang