Mortgage Overpayment Calculator
Find out exactly how much overpaying your mortgage can save you. Enter your remaining balance, rate, term, and the extra amount you can afford each month — see the interest you'll avoid and how much sooner you'll be mortgage-free.
How is this calculated?
We compute the standard amortisation schedule for the original mortgage, then re-simulate it with your overpayment added each month, reducing the balance faster. Interest saved is the gap between original total interest and new total interest. Months saved is the difference between original term and new term. The calculator assumes overpayments are penalty-free — check your mortgage agreement.
Frequently Asked Questions
Should I overpay my Irish mortgage?
Overpaying makes sense when your mortgage rate is higher than your alternative use of money (savings, investment after tax, paying off other debt). At 4% mortgage interest, every €1 of overpayment effectively earns you a guaranteed 4% return. With Irish DIRT at 33% on deposit interest, even a 5% deposit account only nets ~3.35%, so overpaying often wins.
Can I overpay my mortgage in Ireland without penalties?
Most variable-rate Irish mortgages allow unlimited overpayments penalty-free. Fixed-rate mortgages typically allow 10% of the outstanding balance per year — overpaying above that can trigger an early-repayment charge. Always check your loan agreement before making large lump-sum overpayments.
What's better: overpay the mortgage or invest?
It depends on the mortgage rate vs your expected after-tax investment return. If your mortgage rate is 4% and you expect 6% real returns from a diversified equity portfolio, investing is mathematically better — but overpaying is risk-free. Many people split the difference: overpay enough to feel safe, invest the rest.
Does overpaying reduce the term or the monthly payment?
By default, Irish lenders apply overpayments to reduce the term (you pay the same monthly amount, but for fewer months). You can usually request 'recalculation' to lower the standard monthly payment instead — but this doesn't save you as much interest because the balance falls more slowly.
What's the best way to make a lump-sum overpayment?
Contact your lender directly — most allow online or branch lump-sum overpayments. Make sure the lender confirms the payment is applied to capital (not just held as a credit on future payments). Ask for an updated mortgage schedule afterwards to confirm your new term or payment.
Last updated: May 2026 · Rates sourced from Revenue