The Multispectral Thermal Imager (MTI) is a satellite-based imaging system that provides images in fifteen spectral bands covering large portions of the spectrum from 0.45 through 10.7 microns. This article describes the current MTI radiometric image calibration, and will provide contrast with pre-launch plans discussed in an earlier article. The MTI system is intended to provide data with state-of-the-art radiometric calibration. The on-orbit calibration relies on the pre-launch ground calibration and is maintained by vicarious calibration campaigns. System drifts before and between the vicarious calibration campaigns are monitored by several on-board sources that serve as transfer sources in the calibration of external images. The steps used to transfer calibrations to image products, additional radiometric data quality estimates performed as part of this transfer, and the data products associated with this transfer will all be examined.