Methods, systems, and devices for wireless communications are described. A base station may transmit control signaling scheduling a downlink transmission to a user equipment (UE) across multiple bandwidth parts (BWPs) and an indication of a code block group (CBG)-based mapping for the downlink transmission. A transport block (TB) of the downlink transmission may include multiple code block groups (CBGs) that are mapped across the BWPs. The UE may monitor for the TB across the BWPs based on the CBG mapping. For example, the UE may determine the CBGs are mapped across different BWPs based on the cross-BWP CBG mapping. Additionally or alternatively, the UE may determine each CBG is mapped within one BWP based on the cross-BWP CBG BWPs mapping. The UE may calculate a TB size based on available time and frequency resources and may decode the TB based on calculating the TB size and the cross-BWP CBG mapping.