Methodology

Wealth Distribution Data

Wealth share data comes from the World Inequality Database (WID.world), which publishes Distributional National Accounts (DINA) for dozens of countries. These accounts split national wealth into groups:

• Bottom 50% — The lower half of the population by net wealth
• Middle 40%— The 50th to 90th percentile, often called the "middle class"
• Top 10% — The wealthiest tenth, which in most countries holds 60-80% of total wealth
• Top 1% — A subset of the top 10%, typically holding 25-40% of total wealth

These shares define the boundaries used to place you in the distribution. The more granular the boundary data for a country, the more precise the final percentile.

Income-to-Wealth Estimation

Most people know their income but not their net wealth. To bridge this gap, the tool uses an 18-factor estimation model that adjusts the income-to-wealth ratio based on demographic and financial characteristics:

• Age brackets (younger people typically have lower wealth-to-income ratios)
• Education level (higher education correlates with higher lifetime earnings and savings)
• Employment type (self-employed vs. salaried, public vs. private)
• Savings rate and investment behavior
• Property ownership and mortgage status
• Outstanding debts (student loans, consumer debt)

Each factor narrows the uncertainty range. With no factors provided, the model carries a spread of roughly ±70%. With all 18 factors answered, uncertainty drops to approximately ±10%. The tool always shows you the confidence band alongside your estimated percentile.

Percentile Calculation

Once your estimated net wealth is computed, the tool places you in the distribution using piecewise linear interpolation between the known wealth share boundaries. For example, if the bottom 50% holds 5% of total wealth and the middle 40% holds 35%, your position between those boundaries is interpolated linearly based on your estimated share. This is an approximation — real distributions are not perfectly linear between boundary points — but it provides a reasonable estimate given the available data.

Billionaire Comparison

The "How Long Would It Take?" mode uses the Forbes Real-Time Billionaires list to fetch the current net worth of the wealthiest individual in each country.

The "years to earn" calculation is deliberately simple: it divides the billionaire's net worth by your annual income with no adjustments for interest, compound growth, taxes, or inflation. This is intentional — the point is not financial planning but to viscerally illustrate the scale of the gap. When the answer is "4 million years," whether it accounts for a 7% return rate is beside the point.

Limitations

• Top-wealth underestimation — Survey-based wealth data systematically underestimates the holdings of the ultra-rich, who are underrepresented in household surveys. WID partially corrects for this using tax data, but gaps remain.
• Self-reported income bias — Users enter their own income, which may not reflect total compensation (bonuses, equity, unrealized gains).
• Country-specific caveats — Data quality varies by country. Some nations have detailed tax-based wealth data; others rely on survey estimates with wider margins.
• Model approximation — The 18-factor income-to-wealth model is a statistical approximation, not personalized financial advice. Individual circumstances can diverge significantly from population averages.

Data Freshness

All data is bundled at build time and served statically — no external API calls are made when you use the tool. Datasets are updated periodically as new releases become available from WID.world, OECD, SWIID, and Forbes. The build date at the bottom of the page indicates when the data was last refreshed.