Methodology

Most lenders cap monthly mortgage + other debt obligations at 36% of gross monthly income (the front-end DTI ratio). We use that as our maximum.

From the maximum monthly mortgage, we work backwards through the standard amortization formula at the country's average mortgage rate over a 30-year term to find the principal you can borrow.

We add the country's typical minimum down payment to the principal to get the maximum home price.

For example, a 5% down market like the US/UK lets you buy ~5% more home than a 30% down market like Singapore for the same income, because more of the price is leveraged debt.

We do not include closing costs, stamp duty, property taxes, or insurance in the affordability calculation. Add ~3-10% on top depending on country.

Median home prices come from the OECD Housing Database (Q4 2024) and BIS Selected Property Price Series. Where OECD data is missing, we use national statistics offices.

Median household disposable income comes from OECD Income Distribution Database, supplemented with national stats agencies for non-OECD countries.

Both numbers are national medians, so high-cost cities (London, NYC, Tokyo, Sydney) are well above their national median — sometimes 2-3×.

Eurozone: ECB Statistical Data Warehouse 30-year fixed average. UK: Bank of England 75% LTV 5-year fixed. US: Federal Reserve H.15 30-year fixed. Other: national central banks.

Rates are Q1 2025 snapshots. They will drift; the calculator's relative comparisons hold.

These are typical bank policy minimums for first-time buyers, not legal floors:

5% (US, UK, Canada, Denmark) — 10% (France, Germany, Belgium, Netherlands, Australia, Malaysia) — 15% (Sweden, Norway, Finland, Romania) — 20% (Spain, Portugal, Italy, Switzerland, Austria, India, Czech Republic, Hungary) — 25% (Singapore, Israel) — 30% (China, Vietnam, Saudi Arabia, Egypt, Nigeria, Turkey).

Some markets allow government schemes that reduce these — e.g. Help to Buy in the UK (now ended), FHA loans in the US (3.5%), or family-guarantee schemes in Australia. The calculator uses the standard private-bank minimums.

We classify the country median price-to-income ratio into four buckets, following Demographia International Housing Affordability conventions:

Affordable (<4×) — Stretch (4-6×) — Unaffordable (6-10×) — Out of reach (>10×).

These thresholds reflect long-term historical norms. The OECD long-run average from 1990-2010 was ~4.3×. Most rich countries are now well above that.

Down payment needed minus current savings, divided by annual savings (income × your savings rate). Linear; we do not assume returns on savings during the accumulation period.

OECD median household saving rate is around 7%. Higher in Japan, Switzerland, Scandinavia; lower in the UK and Anglo countries.