Confusion of extragalactic sources in the mid- and far-infrared:: Spitzer and beyond

We use the source counts measured with the Multiband Imaging Photometer for Spitzer at 24, 70, and 160 mum to determine the 5 sigma confusion limits due to extragalactic sources: 56 muJy, 3.2 mJy, and 40 mJy at 24, 70, and 160 mum, respectively. We also make predictions for confusion limits for a number of proposed far-infrared missions of larger aperture (3.5 - 10 m diameter).