Buying
Mortgage Repayment Calculator
Work out your monthly mortgage repayment from home price, deposit, interest rate and term, plus how much of each payment goes to interest over time.
Enter your home price, deposit, interest rate and mortgage term below to see your estimated monthly repayment, the total interest you'll pay over the life of the mortgage, and a year-by-year breakdown of your remaining balance.
Your mortgage
= €35,000
Use the rate from your mortgage offer or a lender's quote for an exact figure.
Year-by-year balance
| Year | Principal paid | Interest paid | Balance remaining |
|---|---|---|---|
| 1 | €5,547 | €12,499 | €309,453 |
| 2 | €5,773 | €12,273 | €303,679 |
| 3 | €6,008 | €12,038 | €297,671 |
| 4 | €6,253 | €11,793 | €291,418 |
| 5 | €6,508 | €11,538 | €284,910 |
| 6 | €6,773 | €11,273 | €278,136 |
| 7 | €7,049 | €10,997 | €271,087 |
| 8 | €7,336 | €10,710 | €263,751 |
| 9 | €7,635 | €10,411 | €256,116 |
| 10 | €7,946 | €10,100 | €248,169 |
| 11 | €8,270 | €9,776 | €239,899 |
| 12 | €8,607 | €9,439 | €231,292 |
| 13 | €8,958 | €9,089 | €222,335 |
| 14 | €9,323 | €8,724 | €213,012 |
| 15 | €9,702 | €8,344 | €203,310 |
| 16 | €10,098 | €7,949 | €193,212 |
| 17 | €10,509 | €7,537 | €182,703 |
| 18 | €10,937 | €7,109 | €171,766 |
| 19 | €11,383 | €6,663 | €160,383 |
| 20 | €11,847 | €6,200 | €148,536 |
| 21 | €12,329 | €5,717 | €136,207 |
| 22 | €12,832 | €5,215 | €123,376 |
| 23 | €13,354 | €4,692 | €110,021 |
| 24 | €13,898 | €4,148 | €96,123 |
| 25 | €14,465 | €3,582 | €81,658 |
| 26 | €15,054 | €2,992 | €66,604 |
| 27 | €15,667 | €2,379 | €50,937 |
| 28 | €16,306 | €1,741 | €34,631 |
| 29 | €16,970 | €1,076 | €17,661 |
| 30 | €17,661 | €385 | €0 |
Monthly repayment
€1,504
on a €315,000 mortgage over 30 years
Total repaid
€541,389
Over the full term
Total interest
€226,389
70% of your first payment is interest
Estimates only. This calculator is for general guidance and does not constitute financial, tax, or legal advice. Always confirm figures with Revenue, the RTB, your lender, or a qualified professional before making a decision.
Last reviewed: 20 June 2026. Sources: Competition and Consumer Protection Commission — mortgage calculator guidance.
How this is calculated
This calculator uses the standard fixed-rate amortisation formula that Irish lenders use for repayment mortgages: a constant monthly payment is calculated from your loan amount, interest rate and term, sized so the loan is fully repaid by the end of the term. Each payment is split between interest (charged on the outstanding balance) and principal (which reduces the balance) — the split shifts toward principal as the balance falls.
This is an estimate for a standard fixed-rate repayment mortgage. It doesn't account for rate changes during the term, overpayments, payment breaks, or interest-only periods — your actual lender statement is the authoritative figure.
Frequently asked questions
- How is my monthly mortgage repayment calculated?
- Lenders use a standard amortisation formula based on your loan amount, interest rate, and term. The same fixed monthly payment applies throughout (for a fixed rate), but the split between interest and principal changes over time — early payments are mostly interest, later payments are mostly principal.
- Why does so much of my early payments go on interest?
- Interest is charged on the outstanding balance, which is largest at the start of the mortgage. As you pay down the principal, the balance — and so the interest charged each month — shrinks, even though your total payment stays the same. By the final years of the term, almost all of each payment goes to principal.
- What mortgage interest rate should I use?
- Use the rate from an actual mortgage offer or a lender/broker quote if you have one — rates vary by lender, loan-to-value, and whether you choose a fixed or variable rate. The default rate here is just an illustrative starting point, not a quote.
- Does this include other costs of buying, like stamp duty or legal fees?
- No — this calculator covers the mortgage repayment only. Use the Total Cost of Buying calculator for the full cash you need upfront, including stamp duty, legal fees, and how schemes like Help to Buy or the First Home Scheme reduce that figure.