Indexing a Brussels rent in 2026

Formula, PEB correction factor, the new 2025 base of the health index.

• The formula: base rent × new index ÷ starting index. The starting index is the one for the month before signature, the new index the one for the month before the anniversary.
• Conditions: registered lease, valid PEB certificate given to the tenant, written request, no earlier than the anniversary.
• Lease in force before 14 October 2022 and PEB E, F or G: the result is multiplied by a correction factor that depends on the anniversary date.
• Since January 2026, Statbel publishes the health index in base 2025 = 100. Both indices must use the same base.
• A request only works back three months before the month in which it is made. A PEB given after the anniversary allows no back-pay.

What Autopilot does for you: Computes every anniversary, checks the conditions and prepares the letter in the tenant’s language.