A method and network node for performing link adaption are disclosed. In one embodiment, a channel state information, CSI, measurement is received from a wireless device. An information carrying capacity, ICC, over a number of scheduling blocks, SBs, for a plurality of modulation formats for a target criteria is determined based at least in part on the CSI measurement from the wireless device. A modulation format of the plurality of modulation formats with a maximum ICC is selected. A transport block size, TBS, is determined for the selected modulation format. Link adaptation is performed based on the determined TBS.