The 3-6-9 lease in Belgium: understanding lease duration
The 3-6-9 lease is the standard in Belgium for primary residence leases. Duration, renewal, early termination and exceptions by Region.
The 3-6-9 lease principle
In Belgium, the primary residence lease has a default duration of 9 years divided into three periods of 3 years (triennia). This is the default rule: if the lease does not mention any duration, it is automatically considered a 9-year lease.
This system, inherited from Belgian tenancy law, strikes a balance between stability for the tenant and flexibility for the landlord. At each triennial deadline, both parties have the option to terminate the lease.
The 3-6-9 lease applies to primary residence leases in all three Belgian Regions, with variations on notice periods.
If your lease does not mention a duration or mentions a duration between 3 and 9 years, it is automatically reclassified as a 9-year lease by law. Only short-term leases (less than 3 years) are exempt from this rule.
Early termination
By the tenant
The tenant may terminate the lease at any time subject to a notice period and, in some cases, a compensation:
| Time of termination | Notice period | Compensation |
|---|---|---|
| Year 1 | 3 months (2 in Brussels) | 3 months’ rent |
| Year 2 | 3 months (2 in Brussels) | 2 months’ rent |
| Year 3 | 3 months (2 in Brussels) | 1 month’s rent |
| Years 4 to 9 | 3 months (2 in Brussels) | None |
By the landlord
The landlord may only terminate in three specific cases:
- Personal occupation: 6-month notice period, at any time
- Major renovations: 6-month notice period, at each triennial deadline
- Without grounds: 6-month notice period, only at each triennial deadline, with compensation of 9 to 18 months
To formalise the termination, send a registered letter within the required deadlines.
Differences between the three Regions
| Criterion | Brussels | Wallonia | Flanders |
|---|---|---|---|
| Tenant notice period | 2 months (2026 reform) | 3 months | 3 months |
| Electronic notification | Accepted (2026 reform) | No | No |
| Termination compensation | Identical | Identical | Identical |
| Landlord notice (occupation) | 6 months | 6 months | 6 months |
| Mandatory registration | Yes (free) | Yes (free) | Yes (free) |
The Brussels lease reform 2026 reduced the tenant’s notice period from 3 to 2 months for leases signed from 1 July 2026.
Renewal and end of lease
At the 9-year deadline
If neither party gives notice at least 6 months before the deadline, the lease is tacitly renewed for a period of 3 years under the same conditions (rent, charges, clauses). The rent may be adjusted to market value if both parties agree.
After renewal
The renewed lease works like a new 3-year lease. At its expiry, it is again renewed for 3 years if no notice is given, and so on indefinitely.
For details on tacit renewal of the lease, consult our dedicated guide.
Practical tips
- Always mention the duration in the lease, even if it is 9 years — this avoids ambiguity
- Note the triennial deadlines in your calendar to anticipate a possible termination
- Register the lease within 2 months following signature (free for primary residence leases)
- Keep a copy of the termination notice (registered letter with acknowledgement of receipt)
To create a lease that complies with the 3-6-9 duration rules, use our online lease generator which automatically includes the duration and termination clauses for your Region. For centralised tracking of your deadlines, a rental management software can alert you before each key date.