Abstract. We develop a calibration algorithm and a three-dimensional reconstruction algorithm for a handheld 3D laser scanner. Our laser scanner consists of a color camera and a line laser oriented in a fixed relation to each other. Besides the three-dimensional coordinates of the observed object our reconstruction algorithm returns a comprehensive measure of uncertainty for the reconstructed points. Our methods are computationally efficient and precise. We experimentally evaluate the applicability of our methods on several practical examples. In particular, for a calibrated sensor setup we can estimate for each pixel a human-interpretable upper bound for the reconstruction quality. This determines a "working area" in the image of the camera where the pixels have a reasonable accuracy. This helps to remove outliers and to increase the computational speed of our implementation.