Mortgage Affordability Calculator Ireland

What this calculator is for

Mortgage affordability has at least three different meanings:

1. regulatory borrowing capacity — what the Central Bank loan-to-income and loan-to-value framework permits in a standard case;
2. lender affordability — what a lender is prepared to approve after its own underwriting;
3. household affordability — the repayment you are comfortable carrying while still meeting the rest of your financial commitments.

Those numbers do not have to be the same.

This calculator combines the first and third concepts without pretending to reproduce a lender’s underwriting system.

It compares:

• the standard Central Bank LTI ceiling;
• the mortgage supported by your chosen monthly-payment budget;
• and the mortgage supported by your deposit under a standard 90% principal-home LTV.

The lowest becomes the modelled mortgage ceiling.

Current Central Bank limits

The Central Bank’s current mortgage measures generally cap borrowing at:

• 4 times gross income for first-time buyers;
• 3.5 times gross income for second and subsequent buyers.

Principal-home lending is generally subject to a maximum 90% LTV.

Lenders can use limited allowances above the standard limits under the framework, but a borrower should not plan on receiving an exception.

In 2026 the Central Bank introduced a targeted LTI exemption for qualifying principal-home bridging loans. The exemption is specific to that short-term product type; LTV limits continue to apply.

This calculator models an ordinary purchase mortgage and does not model bridging finance.

Basic mode: a deliberately simple affordability screen

Basic mode uses default scenario assumptions of:

• 4.5% mortgage interest;
• 30-year term;
• maximum mortgage payment equal to 30% of gross monthly household income;
• no other monthly debt.

The 30% figure is not an Irish regulatory rule and is not a lender approval formula.

It is simply a starting assumption so that the calculator can create a monthly repayment constraint alongside the Central Bank limits.

Change it in Advanced mode.

Why a gross-income percentage is only a rough screen

Two households earning the same gross salary can have very different disposable income.

Differences can come from:

• childcare;
• other loans;
• commuting;
• pension contributions;
• variable income;
• health or care costs;
• housing-management fees;
• and ordinary lifestyle commitments.

Gross income is useful for the Central Bank LTI calculation.

It is much less useful as a complete household budget.

That is why Advanced mode includes an optional net-income household budget.

Advanced mode: net-income budget check

If you enter monthly net household income, the calculator creates a second payment limit:

Net income − essential spending − other debt − desired cash buffer

The payment capacity becomes the lower of:

• the gross-income percentage limit after debt;
• and the optional net-income budget limit.

This is still not a lender underwriting formula.

It is a way to make your own affordability ceiling more grounded in cash flow.

If the net-income field is zero, that check is ignored.

Worked example: €80,000 first-time-buyer income

Assume:

• gross household income: €80,000;
• first-time buyer;
• deposit: €40,000.

The standard LTI ceiling is:

€80,000 × 4 = €320,000

The deposit can support a €360,000 mortgage under a 90% LTV framework because a €40,000 deposit is 10% of a €400,000 property.

If the monthly-payment model also supports at least €320,000, LTI becomes the tightest constraint.

The indicative price is then:

€320,000 mortgage + €40,000 deposit = €360,000

That is not mortgage approval. It is the lowest of the modelled constraints.

Worked example: household budget becomes tighter

Suppose the same household enters Advanced mode with:

• €5,000 net household income per month;
• €3,000 essential monthly spending;
• €500 monthly cash buffer;
• no other debt.

The optional budget allows:

€5,000 − €3,000 − €500 = €1,500

for the mortgage payment.

If the gross-income percentage would permit €2,000 per month, the calculator uses the lower €1,500.

At a given rate and term, that monthly capacity may support materially less debt than the LTI ceiling.

That is the distinction between being permitted to borrow and wanting to carry the repayment.

The deposit can still be the binding constraint

Even if income and monthly cash flow are strong, the standard 90% LTV rule can make the deposit the tightest constraint.

The mortgage amount supported by a principal-home deposit under 90% LTV is:

Deposit × 9

For example, €20,000 of deposit cash supports €180,000 of mortgage under that simple LTV arithmetic, corresponding to a €200,000 property.

Use the House Deposit Calculator if you want to explore deposit and LTV separately.

Rate stress test

Advanced mode lets you add a number of percentage points to the entered rate.

The calculator then shows the monthly repayment on the indicative mortgage at that higher rate, over the same term.

This does not replicate a particular lender stress test.

Its purpose is simpler: show whether your chosen mortgage remains comfortable if the interest-rate assumption is worse.

A useful test is to compare:

• the entered rate;
• +0.5 percentage points;
• +1 percentage point;
• and a scenario that would feel uncomfortably high.

If a small rate movement consumes the entire monthly buffer, the household plan has little resilience.

Mortgage term changes affordability and total cost differently

A longer mortgage term normally reduces the scheduled monthly repayment for the same balance and rate.

That can make the payment-based mortgage amount look more affordable.

But a longer term also keeps debt outstanding for longer and can materially increase lifetime interest.

Do not choose a term only because it maximises the result from an affordability calculator.

Use the Mortgage Calculator to compare total interest across terms.

Other debt matters twice

Other monthly debt affects household affordability even though it is not part of the mortgage.

In the gross-income screen, this calculator subtracts other monthly debt from the chosen gross-income payment allowance.

In the optional net-income budget, it also subtracts debt from net household cash flow.

That prevents a car loan or personal loan from disappearing from the affordability model.

The Central Bank LTI calculation itself remains based on the mortgage relative to gross income; the debt deduction is part of your scenario’s cash-flow screen, not a change to the Central Bank ratio.

Lenders perform a broader assessment

CCPC guidance explains that mortgage providers assess an application rather than simply multiplying income by the regulatory limit.

A lender may consider factors such as:

• repayment capacity;
• employment and income evidence;
• existing borrowing;
• dependants;
• age and term;
• credit history;
• and its own internal lending policy.

An actual lender offer may therefore be lower than every number on this page.

Use net income carefully

If you enter net monthly income, use a realistic normal figure.

For variable earners, consider using a conservative level rather than the strongest recent month.

If bonuses or overtime are essential to keeping the mortgage affordable, test the scenario without them.

Also test plausible household changes:

• parental leave;
• childcare starting;
• reduced working hours;
• one income temporarily disappearing;
• or a large recurring expense beginning.

A mortgage can last for decades. Today’s peak household income should not automatically become the permanent baseline.

Preserve a buffer

The Advanced mode asks for a monthly cash buffer because a budget that reaches exactly zero is fragile.

A buffer can absorb:

• annual bills;
• repairs;
• insurance increases;
• energy-cost changes;
• temporary income disruption;
• or simply spending that was underestimated.

The calculator does not prescribe the correct buffer.

Use an amount that reflects the resilience you want to maintain.

Buying costs sit outside the mortgage result

The indicative property price is mortgage plus deposit.

It does not mean you need only the deposit in cash.

CCPC’s home-buying guidance highlights additional costs such as legal fees, Stamp Duty, valuation and insurance.

Use the House Buying Costs Calculator to make sure completion costs do not consume the reserve you assumed in this affordability model.

Common mistakes to avoid

Treating 30% of gross income as an official rule

It is not. It is a user-editable scenario default.

Treating the Central Bank maximum as a comfortable target

A regulatory limit and a household budget answer different questions.

Ignoring other debt

Monthly debt competes for the same household cash flow.

Making the term longer until the result fits

A lower monthly payment can come with more lifetime interest.

Stress-testing only the property price

Stress-test the interest rate and household budget as well.

Using optimistic net income

Use sustainable income, not a temporary high point.

Spending the full deposit reserve

Purchase costs and post-completion cash still need funding.

A practical affordability workflow

1. Enter household gross income and deposit.
2. Note which of LTI, payment budget or deposit/LTV binds.
3. In Advanced mode, replace the default interest rate with a realistic mortgage quote.
4. Set a term you would genuinely accept.
5. Enter other monthly debt.
6. Add net household income and essential spending.
7. Preserve a deliberate monthly buffer.
8. Stress the rate upward.
9. Run the resulting mortgage through the Mortgage Calculator for lifetime interest.
10. Check purchase cash using the House Buying Costs Calculator.

The goal is not to make the calculator display the largest possible property price. It is to understand which constraint is doing the work.

Frequently asked questions

Is the result what a bank will lend me?

No. It is a planning estimate built from the standard LTI/LTV framework and your own affordability assumptions.

Is 30% of gross income a Central Bank rule?

No.

Why does the deposit limit show deposit × 9?

A 10% deposit means a 90% mortgage at the standard principal-home LTV, so the mortgage is nine times the deposit.

Can a lender lend above the standard LTI limit?

The Central Bank framework permits limited lender allowances above standard limits. Availability is not guaranteed to an individual borrower.

Does the 2026 bridging-loan change affect this calculator?

No. This calculator models an ordinary purchase mortgage, not the targeted principal-home bridging product covered by the exemption.

Why does the stress-test payment not change the indicative mortgage?

The stress output is designed to show what the already-calculated indicative mortgage would cost at a higher rate. You can then decide whether to lower your payment assumption or mortgage target and recalculate.

Does this include childcare automatically?

No. Put recurring childcare and other essential costs into the Advanced household-spending field.

Method and limitations

The calculator first calculates the standard LTI ceiling:

gross income × 4 for a first-time buyer, or

gross income × 3.5 for a second/subsequent buyer.

It calculates the standard 90% LTV mortgage supported by the deposit as:

deposit × 9

It then creates a gross-income monthly payment limit:

gross monthly income × chosen payment percentage − other monthly debt

If Advanced mode contains a non-zero net-income figure, it also creates:

net monthly income − essential spending − other debt − desired buffer

The lower monthly payment capacity is converted into a mortgage present value using the entered interest rate and term.

The indicative mortgage is the lowest of:

• LTI ceiling;
• payment-supported mortgage;
• deposit/LTV-supported mortgage.

The stress output recalculates the monthly repayment on that mortgage at the entered rate plus the stress increment.

The model does not reproduce a lender’s underwriting, credit-scoring, income treatment, exceptions process or legal suitability assessment.

Useful sources

• Central Bank of Ireland — Mortgage Measures
• Central Bank of Ireland — What are the mortgage measures?
• CCPC — Understanding mortgages
• CCPC — Applying for a mortgage