Spatial and temporal contrast sensitivity is typically measured using different stimuli. Gabor patterns are used to measure spatial contrast sensitivity and flickering discs are used for temporal contrast sensitivity. The data from both types of studies is difficult to compare as there is no well-established relationship between the sensitivity to disc and Gabor patterns. The goal of this work is to propose a model that can predict the contrast sensitivity of a disc using the more commonly available data and models for Gabors. To that end, we measured the contrast sensitivity for discs of different sizes, shown at different luminance levels, and for both achromatic and chromatic (isoluminant) contrast. We used this data to compare 6 different models, each of which tested a different hypothesis on the detection and integration mechanisms of disc contrast. The results indicate that multiple detectors contribute to the perception of disc stimuli, and each can be modelled either using an energy model, or the peak spatial frequency of the contrast sensitivity function.