How Much House Can You Actually Afford? A Clear Framework
When you apply for a mortgage, the bank's job is to figure out the maximum they can safely lend you without you defaulting. Your job is something different: to figure out the maximum you can borrow while still living the life you want, sleeping at night, and not being one redundancy notice away from financial disaster.
These are not the same number. And the gap between them is where most people who end up "house poor" go wrong.
The 28/36 Rule — A Starting Point, Not a Target
The most commonly cited affordability guideline is the 28/36 rule, used by many lenders when assessing mortgage applications:
- Your monthly mortgage payment should not exceed 28% of your gross monthly income (before tax)
- Your total monthly debt obligations (mortgage + car loans + student loans + credit cards) should not exceed 36% of your gross monthly income
On a gross income of €4,000 per month, 28% is €1,120. That is the mortgage payment a lender will typically be comfortable with. But notice what this rule does not account for: income tax, pension contributions, childcare, car insurance, groceries, utilities, subscriptions, and everything else that comes out of your actual take-home pay.
A More Realistic Framework: The Net Income Method
A more conservative and practical approach is to start from your actual take-home pay:
- Calculate your average monthly take-home pay (net, after all deductions)
- List your current fixed non-housing costs: car payment, loans, subscriptions, childcare
- Estimate variable costs: food, transport, utilities, clothing, entertainment — be honest
- Decide how much you want to save each month for emergencies, retirement, and other goals
- Whatever is left is your maximum comfortable mortgage payment
Most financial advisors suggest that your mortgage payment should be no more than 25–30% of your net take-home pay, with some advocates for housing affordability recommending closer to 20% to leave meaningful breathing room for savings and unexpected expenses.
Real-World Example: Same Income, Very Different Situations
| Factor | Person A | Person B |
|---|---|---|
| Gross monthly income | €4,500 | €4,500 |
| Net take-home | €3,100 | €3,100 |
| Car loan payment | €0 (no car loan) | €320/month |
| Student loan | €0 | €180/month |
| Monthly childcare | €0 (no children) | €600/month |
| Available for housing | ~€1,850 | ~€750 |
| Mortgage a bank might offer | Probably similar for both | |
Both people earn the same salary. A bank assessing affordability on gross income might offer them similar mortgage amounts. But Person B, after their existing obligations, has dramatically less room for housing costs. The bank's offer is the ceiling. Your actual budget is what matters.
The Price-to-Income Ratio
A quick rule of thumb for property prices (not monthly payments) is the price-to-income ratio. Historically, 3–4 times annual gross household income has been a sustainable level for property purchase. Above 5 times income is generally considered stretched; above 6 times is high-risk territory that leaves little margin for rate increases, income disruption, or unexpected costs.
In many European cities, particularly capital cities, current prices are well above these historical norms — which is why the monthly affordability calculation matters more than the ratio alone. A lower ratio does not guarantee comfort if interest rates are high; a higher ratio can be manageable if rates are historically low.
Don't Forget the Costs Beyond the Mortgage
Homeownership comes with costs that renting does not. When assessing affordability, budget for:
- Property taxes or local authority charges — varies significantly by location
- Building insurance — typically required by the lender
- Mortgage protection insurance — often required by the lender
- Maintenance and repairs — a common guideline is to budget 1% of property value per year for maintenance
- Service charges — mandatory for apartments, covering building maintenance and management
- Furnishing costs — often underestimated by first-time buyers
Adding these to your monthly payment estimate gives a much more realistic picture of total housing cost — and is an important part of assessing whether the property you want fits your actual financial situation.
When to Walk Away From a Bank's Offer
Just because a bank is willing to lend it does not mean you should borrow it. Consider declining the full offer if:
- The monthly payment would be more than 30% of your net take-home pay
- You would have less than 3–6 months of expenses saved as an emergency fund after closing
- The payment assumes two incomes and you are not confident both are stable
- You have not stress-tested the payment at 2–3% above the current rate (for variable or short-term fixed loans)
Summary
The right mortgage is not the largest one you qualify for — it is the largest one that fits comfortably within your net take-home pay after all your other obligations, gives you room to save, and leaves you with a buffer for the unexpected. Use the bank's offer as a ceiling, not a target. Start from your actual budget and work backwards to a property price. The result will be a house that genuinely improves your financial life rather than straining it.