Skip to content
Horalis
Theme

Kept only in this tab.

HoralisAll the Horalis tools

Tools

Theme

Kept only in this tab.

Horalis Inflation: what money from back then is worth today

All the research sheets

Translated from the Spanish original. Where they differ, the Spanish one holds.

  • Code: projects/inflation-lens/src/calc.ts (the calculation), src/series.ts (which series and which years each place has), src/view.ts (the sentence, the data line and the timeline).
  • Data: seed-kit's official ones (official data): eurostat-hicp and wb-inflation, and each country's currency from CLDR (countries.json).
  • Tests: projects/inflation-lens/test/calc.test.ts, data.test.ts and site.test.ts.

The question it answers

"What is money from back then worth today?", and the other way round, in any country and in its currency: "€100 of 2010 buys today what ≈ €74 did then", "PEN 100 of 2010 buys today what ≈ PEN 60 did then".

The formula in plain words

Each year's prices come from the year before's and from how much they rose that year. It starts at 100 the year before the first rise. What an amount from a year is worth today is that amount × (today's prices ÷ that year's prices); the other way round, × (that year's prices ÷ today's prices).

Exact: level(y₀ − 1) = 100; level(y) = level(y − 1) × (1 + rate(y) ÷ 100); worth_today = amount × level(today) ÷ level(year). "Today" is the last year of that place's series. Each figure is shown with ≈, in whole units of its currency; below 10, with two significant figures ("≈ AOA 0.23" after a hyperinflation), never a false 0 or 1.

Which series and which years each place has (phase B5)

  1. In the EU (the euro area, the European Union and its 27 countries): Eurostat, HICP, all items, annual average rate of change. The euro area, as it was each year. Each country, in today's currency (euros, złoty, crowns…). Exception: a country that uses the euro today keeps its earlier years, in euros at the fixed conversion rate, as Eurostat publishes them; if it joined the euro after its first year, the page says so beside the result ("Before 2023, in euros at the fixed conversion rate", Croatia; Bulgaria, in the euro since 2026, has all its years like that). An EU country with another currency follows rule 4.
  2. In the other countries: the World Bank, consumer price inflation (FP.CPI.TOTL.ZG). Eurostat is not used for countries outside the EU (its terms do not allow commercial use) nor is the IMF (it asks for permission for commercial use and automated downloads).
  3. The last run of consecutive years of each series: a year without a figure cuts the series (Barbados: no figures from 2020 to 2022, amounts from 2022).
  4. New currencies. A country starts in the first whole year of its current currency, by CLDR's date (currencySince; the same rule as the exchange rates in currencies): the Brazilian real, 1 July 1994 → amounts from 1995. So an amount is never written in a currency that did not exist, and no meaningless figures come out after a hyperinflation with a change of currency. The page says so beside the result: "The data start in 1995, the first whole year that Unicode CLDR gives its current currency (Brazilian real)." It says "that Unicode CLDR gives" because CLDR's date is not always that of a new currency: sometimes it is a change of the country's name or a date of adoption (CFA franc: Burkina Faso, 1984; Central Africa, 1993), and then years are lost needlessly (see What is debatable).
  5. Recent data. Countries whose data end before RECENT do not appear: the year of the World Bank's data minus two (2023 with the 2025 data). Otherwise "today" would be an old year. Left out today, among others: Venezuela (2016), DR Congo (2016), Syria (2019), Sudan and Zimbabwe (2022).

Result (14 Oct. 2026): 178 places (29 from Eurostat). The page says which countries are missing and why: no data, or no data since 2023 ("Venezuela or Cuba, for example").

Assumptions

  • The average of a year's twelve months represents that year's prices.
  • A country's consumer price index measures how what its money buys changes. It is a national average, of an average basket.
  • A place's current currency holds for amounts of any year since it has existed.

Sources, dated

  • Eurostat, prc_hicp_aind (RCH_A_AVG, CP00), to 2024. Reuse with attribution (Decision 2011/833/EU; CC BY 4.0). Provisional: typed by hand (2 October 2026).
  • World Bank, FP.CPI.TOTL.ZG, to 2025. CC BY 4.0. Provisional: from its public mirror on GitHub (the update of 1 July 2026), taken on 9 October 2026.
  • Unicode CLDR: each country's currency and since when (Unicode License v3).

The page states both sources, their years, their licences, the date they were taken and that they are provisional; beside each result, the source and the years of that place.

Validation

  • calc.test.ts: the chained level, what it is worth today and then, the rises, the years without data.
  • data.test.ts:
    • Eurostat: the euro area and the EU close to the weighted average of their countries each year, within their countries; the ECB's average from 1999 to 2019 (1.7 %); the figures checked against Eurostat;
    • the rules: the last consecutive run, the currency's first whole year (the real: from 1995), recent data (Venezuela out), each place once and from its source (the EU from Eurostat; the US, Peru, Japan… from the World Bank).
  • site.test.ts: the same key sentence in euros, soles and yen; the data line; the reason for a country that starts late; the two sources and their licences on the page; the weight (up to 50 KB per page).

Limits

  • National averages. They do not say how much what a particular person buys went up, nor in a city.
  • Different years. "Today" is 2024 in the EU and 2025 almost everywhere else: the sentence says the year.
  • Currencies. A country with a new currency loses the years before. The euro countries keep theirs, in euros at the fixed conversion rate, and the page says so.
  • Short series. There is no minimum of years: Sierra Leone has 2023–2025 (its current leone); Argentina, 2017–2024. The data line says the years.
  • Countries without recent data, or without a series, do not appear (22 without a World Bank series, among them Cuba, Somalia and Turkmenistan).
  • Revisions. The institutes revise their series; the yearly download brings them.

What is debatable

  • The cut by currency loses years the index does have (the World Bank chains the CPI across currency changes). They could be shown in the currency of then, with its fixed conversion rate; it would need a table of redenominations maintained by hand, against the rule of maintaining nothing.
  • CLDR dates that are not new currencies (the CFA franc in Burkina Faso, the Central African Republic, Gabon, Chad and Equatorial Guinea) cut up to 30 years needlessly. An improvement with no maintenance: cut only when CLDR gives that region a different earlier currency. Risk: regions where CLDR does not have the earlier one (Australia) would no longer be cut; it would have to be checked first.
  • The euro countries are treated differently (they keep their years in euros). It is what Eurostat publishes and what users understand ("euros of 1999" in Spain), but it is an exception to rule 4.
  • RECENT (two years) is a choice: with one, more countries would be left out; with three, "today" could be three years ago.
  • Eurostat to 2024. Eurostat has already published 2025; the figures are those typed by hand until the yearly download arrives.

History

  • 14 October 2026. After the independent review: small figures with two significant figures; the euro exception, said on screen and limited to the euro countries (an EU country with another currency follows rule 4); "that Unicode CLDR gives"; the missing countries, on the page.
  • 14 October 2026. New sheet (phase B5 of the Horalis plan): any country, with seed-kit's official data (Eurostat in the EU, the World Bank in the rest); the last consecutive run, the currency's first whole year and recent data. Before, only the EU and the euro area, with src/data/hicp.json (typed by hand), which is withdrawn.