We develop a fast and accurate variable window approach. The two main ideas for achieving accuracy are choosing a useful range of window sizes/shapes for evaluation and developing a new window cost which is particularly suitable for comparing windows of different sizes. The speed of our approach is due to the Integral Image technique, which allows computation of our window cost over any rectangular window in constant time, regardless of window size. Our method ranks in the top four on the Middlebury stereo database with ground truth, and performs best out of methods which have comparable efficiency.