Methodology
What each tool calculates, with which data and from which year, and where it stops being valid.
The same in every tool
Every calculation runs in your browser, with the data inside the page. Nothing you type is sent.
Only official bodies and closed yearly series: no price that changes by the minute, and nothing to keep up by hand.
Every figure says its source and its year beside it, and every limit is on the page.
General information based on historical data. It is not personalised financial advice, nor a recommendation to buy.
Horalis Growth
What it calculates
- How much your money could grow: what you have, what you add each month and for how many years, at a growth you choose or an investment's past.
- How much it could give you a month today: the largest yearly withdrawal that lasted 30 years from every start year in that investment's data, the worst included.
With which data
- Yearly returns after inflation: US stocks (Robert Shiller), German government bonds (OECD, Destatis) and gold (World Bank). Living costs and exchange rates: the World Bank.
Where it stops being valid
- The past does not promise the future. Returns count no taxes, fees or changes between currencies.
- A country's cost of living is a national average, not a city.
- Bonds and gold have few 30-year periods in their data: a rough guide.
Horalis Glossary
What it calculates
- What a money word means, with an example in numbers and its formula when there is one.
With which data
- Terms written for Horalis, in one public file with its version; each formula checked against its own example.
Where it stops being valid
- Short, general definitions: not a textbook or advice. Some words differ by country or law; the glossary gives the general sense.
Horalis Yield Curve
What it calculates
- The euro area yield curve: the 10-year minus the 3-month rate, month by month since 2004, with the recessions shaded.
With which data
- The ECB Data Portal (euro area AAA yield curve); recession dates from the CEPR-EABCN committee. Updated once a year, or by you, straight from the ECB.
Where it stops being valid
- A historical signal, not a forecast: it has failed and given false alarms. Only three recessions since 2004. Not a recommendation.
The data
The official series and the yearly returns the tools use, with source, years and licence. Horalis Growth lists its other figures on its How it works page.
| Series | Source | Years | Licence |
|---|---|---|---|
| Inflation, consumer prices (provisional) | World Bank, World Development Indicators | 1960–2025 | CC BY 4.0 |
| Official exchange rate (provisional) | World Bank, World Development Indicators | 1960–2025 | CC BY 4.0 |
| Purchasing power parity (provisional) | World Bank, World Development Indicators | 1990–2025 | CC BY 4.0 |
| Price level (provisional) | World Bank, World Development Indicators | 1990–2024 | CC BY 4.0 |
| Household surveys: average income or spending (provisional) | World Bank, World Development Indicators | 2004–2023 | CC BY 4.0 |
| Harmonised index of consumer prices (EU) (provisional) | Eurostat | 1997–2024 | CC BY 4.0 |
| US stocks, returns after inflation | Robert Shiller, Yale University | 1928–2022 | Published openly; used with credit |
| German government bonds, returns after inflation | OECD (Bundesbank data), Destatis | 1988–2024 | OECD: CC BY 4.0; Destatis: dl-de/by-2-0 |
| Gold, returns after inflation | World Bank, Pink Sheet | 1988–2024 | CC BY 4.0 |
Provisional: not yet downloaded from the source's own site. The page of each tool says so.
When a method changes
No method or assumption changes without its research sheet, which says what changed, why and which tests check it. The research sheets are public.
Updated on 15 October 2026.