The formula
Indexation is calculated as: base rent × new index / starting index. The index used is the health index, published monthly by the FPS Economy. Indexation may only occur once per year, on the lease anniversary date.
EPC exceptions
In Brussels, properties with an EPC certificate of category E, F or G can no longer index their rent. In Wallonia, a similar ban applies to labels F and G. In Flanders, indexation remains possible but limited for labels E and F.