Calculates the total rent owed, including partial periods, for a residential tenancy in Ireland. For landlords and tenants to formalise arrears.
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Rent Increase Rules in Ireland
In Ireland, rent increases for most private residential tenancies are governed by legislation that was significantly expanded on 11 March 2026. From that date, the 2% cap on rent increases, which previously applied only in designated Rent Pressure Zones (RPZs), was extended to cover the entire country. This means that for any rent review taking place on or after 11 March 2026, the amount a landlord can increase the rent is legally capped at 2% or less, regardless of the property's location.
The primary purpose of these rules is to moderate rent inflation and provide tenants with greater predictability in housing costs. Understanding how to calculate the maximum permissible increase is essential for both landlords, to remain compliant with the law, and tenants, to know their rights.
How the Maximum Rent Increase is Calculated
The calculation follows a specific formula set out in the Residential Tenancies Acts:
- Determine the Base Rent: This is the rent amount currently being paid.
- Check the Timing: A rent review can only take place once every 12 months (365 days). The date of the proposed new rent must be at least one full year after the date the current rent amount took effect.
- Find the Correct Percentage: The allowable increase percentage is the lower of:
- The annual percentage change in the Harmonised Index of Consumer Prices (HICP), published by the Central Statistics Office (CSO). The specific figure to use is for the 12-month period ending the month before the proposed new rent date.
- Or 2%.
- Apply the Percentage: Multiply the current rent by the applicable percentage to find the maximum increase in euro. Add this amount to the current rent to find the highest new rent you can charge.
Example Calculation
Imagine a tenancy with a current monthly rent of €1,600. The last rent increase took effect on 1 July 2025. The landlord wishes to propose a new rent from 1 July 2026.
- Step 1: The 12-month rule is satisfied (1 July 2025 to 1 July 2026 is more than 365 days).
- Step 2: The landlord must find the official HICP percentage for the 12 months ending June 2026 (the month before the proposed new rent date). Let's assume the CSO publishes this figure as 1.7%.
- Step 3: The applicable percentage is the lower of 1.7% and 2%, which is 1.7%.
- Step 4: The maximum increase is 1.7% of €1,600, which is €27.20.
- Step 5: The maximum permissible new rent is €1,600 + €27.20 = €1,627.20.
The landlord cannot legally set the new rent above €1,627.20 from 1 July 2026.
Frequent Scenarios
- First Rent Review: If there has never been an increase, the "date of last rent review" is the tenancy start date. The 12-month period runs from that start date.
- HICP is Higher Than 2%: If the official HICP figure is 2.5%, the allowable increase is only 2%.
- Proposing an Increase Too Soon: If you try to increase the rent 11 months after the last review, no increase is permitted, regardless of the HICP figure.
- Finding the HICP Figure: The correct HICP percentage is published monthly by the CSO in table CPM16. You need the "12-month percentage change" for the month that is one month before your proposed new rent date. There is no default value; you must look it up.
Next Steps and Documentation
Once you have calculated the maximum permissible new rent, you must formally notify the tenant in writing. This notice must include the amount of the new rent, the date it takes effect, and a link to the RTB website or this calculator showing how the amount was determined.
For new tenancies or to formalize a rent increase in an existing agreement, using a proper Residential Lease Agreement or adding a rent review addendum is advisable. This ensures all terms are clear and legally documented, protecting both landlord and tenant.