Mortgage top-up calculator examples Ireland
See how different top-up amounts could affect monthly repayments using illustrative mortgage calculations.
Page checked: 21 October 2026
Illustrative top-up repayments
At the site's illustrative 3.53% rate, adding borrowing over 20, 25 or 30 years produces different payments. For example:
| Top-up | 20 years | 25 years | 30 years |
|---|---|---|---|
| €20,000 | €116 | €100 | €90 |
| €50,000 | €291 | €251 | €225 |
| €100,000 | €582 | €502 | €451 |
Illustrations only. Actual top-up rates and terms vary.
The term matters
Adding a top-up over a long mortgage term can reduce the monthly payment while increasing the total interest. Compare the full cost, not just the monthly figure.
Use the mortgage calculator and enter the additional borrowing as the mortgage amount for a simple repayment illustration.
Sources & assumptions
Central Bank mortgage-measure limits and Revenue stamp-duty rules can change. Check the official sources before relying on an estimate.
Central Bank mortgage measures · Central Bank retail interest rates
How to read these top-up examples
The table above assumes the additional borrowing is repaid as a standard capital-and-interest mortgage at the illustrative rate shown. It isolates the new borrowing to make the term comparison easier; it does not calculate your lender's approval, fees or the combined effect on your existing mortgage.
Before using the figures, check three things with your lender: the rate and term available for the top-up, whether fees need to be added, and whether the new borrowing is repaid separately or combined with the existing balance. If the purpose is to consolidate debt, compare the total interest over the full term with the cost of keeping the original debts on their current terms.
Use the mortgage top-up guide for eligibility considerations and the top-up versus personal loan comparison before deciding which option to investigate.