Example result based on the prefilled values.
Fixed
€1,192.60/mo
Variable
€1,145.99/mo
Difference
€46.61/mo
Continue your plan
Useful next calculations
When to use this calculator
- Before comparing lenders, brokers, or repayment options.
- When you want to test how a different deposit, rate, or term changes affordability.
- When you need a quick estimate before using a formal quote or agreement in principle.
- When you are stress-testing your budget against a potential rate rise to see the impact on monthly payments.
- When you want to understand the full cost of borrowing — not just the monthly figure — before you commit.
A realistic Ireland planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Loan Amount (€)
€280,000
Fixed Rate (%)
5%
Variable Rate (%)
5%
Term (Years)
25 years
After entering these figures, review fixed, variable and difference together rather than in isolation — each metric tells a different part of the story. Then rerun the tool with one input adjusted to see which variable has the biggest effect on all three outputs before you settle on a plan.
How to read your results
Fixed
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Variable
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Difference
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Method & assumptionsAuthoritative sources
This calculator compares the total cost of a fixed-rate mortgage against a variable or tracker mortgage over a chosen time horizon. For the fixed rate, the monthly payment and total cost are straightforward to calculate and remain constant throughout the comparison period. For the variable option, the calculator uses the current rate to project costs, with an optional rate-rise scenario so you can stress-test your budget. The comparison period is important: if it does not align with the end of a fixed deal, exit costs may apply. The tool does not model rate changes dynamically over time, and actual tracker costs will depend entirely on how the Bank of England base rate moves. This is a planning tool, not a guarantee of future costs.
Common mistakes
- !Using an assumption that is not supported by a current local quote, bill, statement or official source.
- !Treating a generic estimate as a lender, provider, payroll or tax authority decision.
- !Mixing monthly and annual inputs without converting them consistently.
- !Forgetting location-specific taxes, fees, eligibility rules or payroll deductions where they apply.
- !Testing only one scenario instead of checking how a cautious assumption changes the result.
What to do next
- Run a second scenario with a cautious assumption so you can see the downside clearly.
- Compare the result with the related calculators below before making a decision.
- Check current local rules, eligibility and provider terms before applying or committing money.
- Keep a record of the assumptions so you can update the estimate when a quote, bill or pay figure changes.
- Use the result to prepare better questions for a lender, provider, adviser or employer rather than treating it as a final answer.
Frequently asked
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