A regulator has now added official battery ratings for each member of the new iPhone 13 flagship series to its database. These stats indicate that the devices have improved in terms of the important metric in question by at least 11% per variant compared to their respective predecessors. The results might make Apple's claims of increased screen-on time in this generation a reality.
https://www.notebookcheck.net/Initial-independent-iPhone-13-series-battery-capacity-findings-hint-at-gains-of-up-to-18-5-over-the-previous-generation.562766.0.html