Mortgage Calculator

How this mortgage calculator works

The monthly repayment is calculated with the standard capital-and-interest annuity formula used by every Irish lender: P × (r(1+r)n) / ((1+r)n − 1), where P is the loan amount (purchase price minus deposit), r is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly payments (term in years × 12). The rate you enter is held constant across the full term — real Irish mortgages typically mix a short fixed period with a variable rate afterwards, so treat the result as the repayment you would pay if today's rate held for the life of the loan.

The amortisation table shows how each monthly payment splits between interest (high at the start, falling as the balance reduces) and principal (low at the start, rising as the balance reduces). Early overpayments cut total interest paid disproportionately because they hit the balance at its largest.

What this calculator does not include: mortgage protection insurance (~€20–€60/month, required by every Irish lender), home insurance, life cover, valuation or legal fees on drawdown, stamp duty (1% of price up to €1m, 2% above), or tax relief on interest for buy-to-let properties. It also holds the rate constant; if you are on a fixed-for-3 deal with a variable thereafter, repayments will change when the fix ends. For the all-in annual cost including mandatory fees, compare lenders' APRC, not just the headline rate.

Worked example — €400,000 Dublin home, first-time buyer

Suppose you are buying a €400,000 home in Dublin as a first-time buyer. Under Central Bank loan-to-value rules you need a minimum 10% deposit (€40,000), so the loan amount is €360,000. At a 4.5% interest rate over a 30-year term, your monthly repayment works out to roughly €1,824. Over the full 30 years you would pay back approximately €656,500 in total — of which €296,500 is interest, almost as much as the loan itself.

Shortening the term to 25 years pushes the monthly repayment to around €2,001 but cuts total interest to about €240,300 — a saving of €56,200 over the life of the loan. Increasing the deposit to 20% (€80,000, which would require either a non-first-time purchase or a lender exception) drops the monthly to about €1,621 and total interest to about €263,500. Each of those numbers can be reproduced by entering the same inputs into the sliders above.

If you are not sure what purchase price is achievable on your income, the affordability calculator applies the Central Bank's loan-to-income rules to give you a realistic upper bound.