Methodology
This page explains the core assumptions behind the calculator: where the data comes from, how percentile placement works, and where the model is approximate.
Wealth Distribution Data
Wealth-share data mainly comes from WID.world. The site uses percentile group boundaries such as the bottom 50%, middle 40%, top 10%, and top 1% to place your wealth into a national distribution.
Income-to-Wealth Estimation
When you enter income rather than net wealth, the site estimates a likely wealth range using additional demographic and financial factors. This narrows uncertainty, but it remains an estimate.
Percentile Calculation
Your estimated wealth is mapped onto known percentile anchors using interpolation. Real-world wealth distributions are not perfectly linear, so the result should be treated as an informed approximation.
Billionaire Comparison
The comparison mode uses billionaire net-worth snapshots and divides that wealth by your annual income. It intentionally ignores taxes, spending, and compound returns because the goal is scale, not personal planning.
Tax Rate Data Sources
Effective tax-rate comparisons are compiled from academic papers and official statistics. Unlike the wealth distribution data, these sources are not available through one standardized API.
| Country | Source | Year |
|---|---|---|
| 🇦🇺Australia | ATO Taxation Statistics; Leigh (2009, updated); Grattan Institute distributional analysis | 2022 |
| 🇦🇹Austria | Statistik Austria, Integrierte Lohn- und Einkommensteuerstatistik (integrated wage and income tax statistics). Social contributions ~18% employee share, capped. Flat 27.5% KESt on capital income reduces effective rates for top brackets. Sub-percentile rates estimated from capital income concentration data. | 2023 |
| 🇧🇪Belgium | Statbel fiscal income statistics (decile distribution of net taxable income, total tax, and average tax rate, income year 2023). Very high social contributions (~13% employee). No general capital gains tax; 30% withholding on dividends. Sub-percentile rates estimated from OECD/WID capital income concentration. | 2023 |
| 🇧🇷Brazil | Receita Federal; Morgan (2017), WID.world; Gobetti & Orair (2017) | 2021 |
| 🇨🇦Canada | Statistics Canada; PBO Distributional Analysis 2023; OECD Tax Database 2024 | 2022 |
| 🇨🇱Chile | SII (Servicio de Impuestos Internos) bracket data; WID.world Chile distributional accounts; López & Figueroa (Harvard CID). Highly regressive due to 19% IVA consumption tax burden on lower incomes and favourable capital income treatment. Top 1% earn ~25% of pre-tax income (WID). Sub-percentile effective rates estimated. | 2024 |
| 🇩🇰Denmark | Danish Ministry of Taxation; OECD Tax Database 2024; WID.world Denmark series | 2022 |
| 🇫🇮Finland | Statistics Finland income distribution statistics; Verohallinto public tax data. Finland's dual income tax system: progressive earned income tax up to ~51.4%, flat 30–34% capital income tax. Sub-percentile rates estimated from capital vs labour income shares. OECD Taxing Wages 2025: average net tax rate 30.3%. | 2023 |
| 🇫🇷France | Landais, Saez & Zucman (2020); WID.world France series; EU Tax Observatory (2024) | 2022 |
| 🇩🇪Germany | Bach, Beznoska & Steiner (2020), DIW Berlin; Bundesfinanzministerium Datensammlung; OECD 2024 | 2021 |
| 🇮🇪Ireland | Revenue Commissioners income tax distribution tables; CSO Ireland's Tax Statistics 2024; Social Justice Ireland effective rate analysis (10.3% at €25K, 39.0% at €120K). Top rate = 40% income tax + 8% USC. Top 1% (>€203K) pay ~19% of personal tax. Entrepreneur relief (10% CGT) benefits top brackets. | 2024 |
| 🇮🇹Italy | Ministero dell'Economia; Acciari & Morelli (2023); EU Tax Observatory (2024) | 2022 |
| 🇯🇵Japan | National Tax Agency statistics; Moriguchi & Saez (2008, updated); OECD Tax Database 2024 | 2022 |
| 🇳🇿New Zealand | NZ Inland Revenue, High-Wealth Individuals Research Project (April 2023): median effective rate of 8.9% for 311 high-wealth individuals on economic income incl. unrealised gains, vs 20.2% for middle NZ. Lower brackets from NZ Treasury distributional analysis. No general capital gains tax. | 2023 |
| 🇳🇴Norway | Alstadsæter, Johannesen & Zucman (2019); SSB tax statistics; WID.world Norway series | 2021 |
| 🇿🇦South Africa | SARS Tax Statistics; Chatterjee, Czajka & Gethin (2022), WID.world; National Treasury | 2021 |
| 🇪🇸Spain | Agencia Tributaria; Alvaredo & Saez (2009, updated); EU Tax Observatory (2024) | 2022 |
| 🇸🇪Sweden | Waldenström (2020), IFN Stockholm; SCB tax statistics; WID.world Sweden series | 2021 |
| 🇨🇭Switzerland | Swiss Federal Tax Administration; Brülhart et al. (2022); OECD Tax Database 2024 | 2022 |
| 🇳🇱The Netherlands | CPB Netherlands Bureau; CBS income statistics; EU Tax Observatory (2024) | 2022 |
| 🇬🇧United Kingdom | Advani, Chamberlain & Summers (2023); HMRC Survey of Personal Incomes; ONS household data | 2022 |
| 🇺🇸United States | Saez & Zucman (2019), The Triumph of Injustice; updated with IRS microdata through 2018 | 2018 |
Effective tax rates include all taxes: income, payroll, corporate (allocated to shareholders), property, estate, and consumption taxes, divided by total pre-tax economic income. Sources combine academic research, government tax statistics, and the EU Tax Observatory Global Tax Evasion Report (2024). Tax rate data is not API-fetchable and is maintained manually from published government statistics and academic papers.
Limitations
- Top-end wealth is difficult to measure and may still be understated, even in improved datasets.
- Income-based estimation is statistical rather than personalized financial accounting.
- Data quality varies by country, especially where tax-based wealth records are limited.
Data Freshness
The site bundles data at build time. It does not make live API calls in the browser, so updates depend on rerunning the fetch pipeline and rebuilding the site.