Loan Interest Calculator Ireland
Calculate monthly repayments, total interest, and the full cost of any personal, car, or business loan. See how much extra you pay by extending the term — and how overpayments save interest.
For planning purposes only — confirm rates and terms with your lender.
Loan Details
Loan Summary
Enter your loan details above to calculate repayments.
What this calculator does
This tool calculates the monthly repayments and total interest cost of a standard amortising loan — the type used for personal loans, car finance, and most business term loans. You enter the loan amount, interest rate, and term; it shows you the required monthly payment, the total interest you will pay, and the full repayment schedule month by month.
The optional overpayment field shows how making extra monthly payments reduces the total interest and pays off the loan earlier.
How loan repayments are calculated
Standard repayment loans use the annuity formula (also called the PMT formula). Each month, interest accrues on the outstanding balance, and your fixed monthly payment covers the interest first, with the remainder reducing the principal.
Where: P = loan amount, r = monthly interest rate (annual rate ÷ 12), n = total number of monthly payments (years × 12).
Why early payments are mostly interest
In the early months, your balance is highest — so more of each payment goes to interest and less reduces the principal. As the balance falls, the interest component shrinks and more goes to capital. This is why making overpayments early in a loan is most effective — it reduces the balance on which future interest accrues.
Total interest cost
The longer the term, the more interest you pay — even though monthly repayments are lower. A €20,000 loan at 7% over 10 years costs nearly twice as much in interest as the same loan over 5 years.
Worked examples
Example 1 — Personal loan €10,000 at 8% over 3 years
| Item | Value |
|---|---|
| Loan Amount | €10,000 |
| Annual Rate | 8% APR |
| Monthly Rate | 0.667% |
| Term | 36 months (3 years) |
| Monthly Repayment | €313.36 |
| Total Repaid | €11,281 |
| Total Interest Cost | €1,281 |
Example 2 — Car loan €25,000 at 6.5% over 5 years
| Item | Value |
|---|---|
| Loan Amount | €25,000 |
| Annual Rate | 6.5% APR |
| Term | 60 months (5 years) |
| Monthly Repayment | €489.46 |
| Total Repaid | €29,368 |
| Total Interest Cost | €4,368 |
Example 3 — Business equipment loan €50,000 at 5.5% over 7 years, with €200/month overpayment
| Item | No Overpayment | With €200/mo Overpayment |
|---|---|---|
| Monthly Payment | €721 | €921 |
| Loan Paid Off In | 84 months (7 years) | ~63 months (5.25 years) |
| Total Interest | €10,564 | ~€7,800 |
| Interest Saved | — | ~€2,764 |
An extra €200/month saves ~€2,764 in interest and pays off the loan nearly 21 months early.
How to interpret your result
Monthly payment versus total cost trade-off
Longer loan terms reduce monthly payments but significantly increase the total interest paid. A €30,000 loan at 7%:
- Over 3 years: €926/month — total interest: €3,350
- Over 5 years: €594/month — total interest: €5,640
- Over 7 years: €451/month — total interest: €7,870
The 7-year option costs €4,520 more in interest than the 3-year option, despite having a monthly payment that is less than half the amount. This trade-off is real money — choose the shortest term your budget can support.
Interest rate versus term — what matters more?
On short-term loans (1–3 years), the interest rate has a relatively small absolute impact. On longer loans (5–10 years), even a 1% difference in rate can cost thousands of euro in additional interest. Negotiating a better rate matters more on long-term borrowing; on a 2-year loan, the difference in monthly repayments between 7% and 9% on €10,000 is only about €10/month.
Common mistakes when taking out a loan
- Only comparing monthly repayments: A lower monthly repayment almost always means a longer term and more total interest. Always look at the total cost of credit (total repayable), not just the monthly figure.
- Not checking for early repayment charges: Some loans in Ireland charge a fee if you repay early or overpay significantly. Credit unions typically allow overpayment without penalty; bank personal loans may not. Check the terms before signing.
- Ignoring payment protection insurance (PPI): Some lenders bundle PPI into loans, significantly increasing the effective cost. PPI is rarely good value — consider whether you need it and whether cheaper alternatives exist.
- Borrowing more than needed: Lenders often offer a higher loan amount than requested. Taking the extra "because it's there" increases your total interest cost and monthly commitment. Borrow the minimum you need.
- Not considering a credit union first: Irish credit unions typically offer more competitive personal loan rates than banks, especially for amounts under €25,000. If you are a member of a credit union, compare their offer before going to a bank.
Frequently Asked Questions
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Built by a finance professional, for Irish SMEs.
Shuppa's finance tools are built by Gerard Fox — a commercial finance professional with ACCA-level expertise and over a decade operating inside financial planning, budgeting, and operational performance. These tools exist because the right tools for Irish businesses didn't.