Rent arrears calculator (Portugal)
Enter the rent and how many months are unpaid: we add up the debt, apply the 20% penalty the law provides for and prepare the letter to send to your tenant.
How the amount owed is calculated
- The base is simple: monthly rent multiplied by the number of months due and unpaid.
- On top of the debt comes a 20% penalty, set by article 1041 of the Civil Code. It is not an optional charge: it is what the law fixes for late payment of rent.
- That penalty is owed even if the tenant pays later, within the first 8 days of default.
- If the lease provides for extra charges (building fees, water, electricity billed to the tenant), those add up separately, outside the rent calculation.
The deadlines that actually matter
Rent falls due on the first working day of the month before the one it covers, unless the lease says otherwise. Default is counted from there. If the tenant pays the rent plus the 20% penalty within the first 8 days of default, that payment blocks immediate termination of the lease. After those 8 days the breach is consolidated and counts towards repeated lateness.
What each situation allows you to do
| Situation | What you can do |
|---|---|
| Up to 8 days late | Claim the rent and the 20% penalty. Payment within this window blocks termination of the lease. |
| 1 month of unpaid rent | Send a written demand and claim rent plus 20%. Not yet enough to terminate the lease. |
| 2 months or more unpaid | Terminate the lease and start eviction, through the BAS desk or the courts. |
| Repeated lateness | More than 8 days late, 3 to 4 times within a 12 to 18 month period, is also grounds for termination. |
Eviction: how it is done (and how it never is)
Getting the property back goes through the landlord and tenant desk (BAS), which took over the special eviction procedure from the former national tenancy desk, or through court proceedings when the case falls outside the simplified route. Never by your own hand: changing the locks, removing the tenant’s belongings or cutting off water and electricity is illegal, may amount to a criminal offence and wrecks the landlord’s position in the case.
Frequently asked questions
Is the 20% penalty automatic?
It is owed by law from the moment of default, but it has to be claimed. In practice, state it expressly in your demand letter and in the amounts you claim, otherwise the tenant will pay the rent alone.
Can I charge late interest instead of the 20%?
In urban tenancies, article 1041 of the Civil Code sets the indemnity at 20% of the amount owed, and that is the regime that applies to late rent. Ordinary civil interest is not freely added on top of it.
The tenant paid on day 5. Can I still terminate the lease?
No. Payment within the first 8 days of default blocks immediate termination. You can still claim the 20% penalty and, if the lateness repeats, those episodes count towards termination for repeated lateness.
Do I need a lawyer?
Not for the written demand. For the special eviction procedure or a court action it is strongly advisable, especially if the tenant contests or raises defects in the property.
Should I keep issuing rent receipts?
You only issue a receipt for what you actually receive. Unpaid rent generates no receipt, but it should be recorded as debt for evidence and tax purposes.
Do not let it reach two months
The platform flags unpaid rent the day after it falls due, emails you an alert and keeps the payment history that serves as evidence.
Try free for 14 daysRead the full guide: my tenant is not paying the rent
Informative tool, not a substitute for legal advice. Always check your lease clauses and the legislation in force.