"Is it cheaper to rent or buy?" is usually asked as if the answer is a single number — but a fair comparison needs more than just rent versus the mortgage repayment. Done properly, it accounts for what your deposit could otherwise earn, the costs of ownership a tenant never sees, and how long you actually plan to stay.
Why comparing rent to the mortgage payment alone is misleading
A mortgage repayment on a given home is often similar to, or even lower than, the rent on an equivalent property — which makes buying look like the obvious choice on a monthly view. But that comparison leaves out several real costs and benefits on both sides:
- The opportunity cost of your deposit. A 10% deposit on a home is a large sum that would otherwise sit in savings or investments, potentially earning a return. Buying spends that lump sum on home equity instead — which may or may not outperform the alternative, depending on how the property's value moves.
- Ownership costs a tenant doesn't pay. Buildings insurance, maintenance and repairs, and (where applicable) management fees fall entirely on the owner. A reasonable estimate is commonly cited as somewhere around 1–1.5% of the home's value per year, though it varies a lot by property age and type.
- Buying and selling costs. Stamp duty, legal fees, and survey costs when buying; estate agent and legal fees when eventually selling. These are real costs that a pure rent comparison ignores entirely.
- What happens to the rent and the home's value over time. Rent tends to rise (see our Rent Increase guide for the rules governing how much), and home values can rise or fall — both affect the comparison the longer you hold.
The variable that matters most: how long you'll stay
Buying carries large upfront costs (stamp duty, legal fees, deposit) that are effectively "sunk" the day you complete — they don't shrink if you move out a year later. The longer you stay in a home, the more those upfront costs are spread out, and the more time your equity has to benefit from any home value growth. This is why the same numbers can favour buying over a 10-year horizon and favour renting over a 2-year horizon, even with identical rent and mortgage figures.
What the comparison can't tell you
No calculator can tell you whether buying is the "right" choice for your life — only the right choice financially, under the assumptions you put in. Job mobility, family plans, how much you value the stability (or flexibility) of each option, and how comfortable you are taking on mortgage debt are all real factors a cost comparison doesn't capture.
It's also worth being honest about how sensitive these comparisons are to assumptions that are genuinely uncertain — nobody can predict house price growth, rent inflation, or investment returns with confidence over a 10-year horizon. Small changes to those assumptions can flip the answer, which is why it's worth testing a few different scenarios rather than trusting a single result.
Using the calculator
Our Rent vs Buy calculator runs this full comparison: it takes your home price, deposit, mortgage rate and term, and compares the total cost of buying against renting the same standard of home and investing the difference, over whatever time horizon you choose. Every assumption (mortgage rate, home appreciation, rent inflation, investment return) is visible and adjustable — they're starting points, not predictions, and the result is only as good as the assumptions behind it.
Frequently asked questions
Does the calculator factor in mortgage interest relief or tax benefits? No specific mortgage interest tax relief currently applies to owner-occupiers in Ireland in the general case, so the calculator doesn't model one — if your situation involves a specific relief, treat the calculator's result as a starting point, not the final word.
What mortgage rate should I use? Use the actual rate quoted to you, or a current representative rate if you haven't gotten quotes yet — rates vary by lender, loan-to-value, and whether it's fixed or variable, so the calculator's default is just a reasonable mid-2026 starting point, not a quote.
Should I include Central Bank mortgage lending rules in this comparison? The Central Bank's loan-to-income and loan-to-value limits affect how much you can borrow in the first place, not the rent-vs-buy comparison itself — if you're not sure whether you'd qualify for the mortgage size you're comparing, that's worth checking with a lender or broker before relying on the comparison.