Landlords
Mortgage interest on a rental property: what you can claim
Last updated 16 October 2026
Landlords can deduct 100% of the interest on a loan to buy, improve or repair a let home. The tenancy must be registered with the Residential Tenancies Board.
Interest on money borrowed to buy, improve or repair a let property is one of a landlord's biggest deductions. For residential lettings, 100% of the interest is allowed against rent. Capital repayments are never allowed: only the interest part of each mortgage payment counts.
The conditions
- the loan must have been used to buy, improve or repair the property you let
- for residential property, every tenancy must be registered with the Residential Tenancies Board
- the interest must relate to a time the property was let, or between lettings while you didn't live there
When interest isn't allowed
- from the day you bought the property until it was first let (unless the pre-letting rules for vacant homes apply)
- between lettings if you, or anyone rent-free, lived there
- on any part of a loan used for something other than the property, such as a top-up spent on a car
What registering the tenancy is worth
A landlord on a €60,000 salary lets a house for €20,000 a year and pays €8,000 of mortgage interest in 2026.
| Taxable rent with every tenancy registered | €9,000.00 |
| Tax on the rent | €4,251.38 |
| Taxable rent if the tenancy isn't registered | €17,000.00 |
| Tax on the rent | €8,378.18 |
| Cost of not registering | €4,126.80 |
At a 40% income tax rate plus USC and PRSI, each euro of interest is worth close to half a euro in tax. Registration also matters for Rental Income Relief.
Commercial and foreign property
For shops, offices and land, interest on a loan to buy, improve or repair the property is deductible without any need to register a tenancy. For property abroad, interest is allowed only for the time it is let; see foreign rental income.
Where it goes on the return
On Form 11, residential interest goes at line 205(b) and commercial interest at line 212(b). Keep your lender's annual interest certificate: it splits interest from capital.
Work it out
Sources
- Revenue: Irish rental income: what expenses are allowed? (checked 25/10/2026)
- Revenue: Irish rental income: what expenses are not allowed? (LPT, pre-letting, own labour) (checked 16/10/2026)
- Revenue: Rental profit and losses (worked example, capital allowances before losses) (checked 16/10/2026)
General information, not tax advice. HeyPenny is not a tax agent.