Home / About
About, data
& copyright
How the figures are measured, where they come from, who owns what, and what this site does not claim.
Copyright & licence
- Site, code and texts: © 2026 Rogzy, under the MIT licence. Reuse them, commercially too, as long as you keep the copyright and licence notice.
- Banknote images: scans from David St-Onge’s collection, shown with his permission. They are not covered by the MIT licence: the downloads are for personal and educational use; any other reuse needs his permission.
- The banknote designs belong to the central banks and governments that issued them. Almost all were withdrawn long ago; a few recent ones (Lebanon 2021, Venezuela 2020) may still be legal tender and are shown for history and education, not for reproduction.
- Library: books, covers and descriptions from Plan B Network’s open educational content (CC BY-SA 4.0); the book covers belong to their publishers.
- Third parties: fonts from Google Fonts (Archivo, IBM Plex Mono).
How the data works
What counts as a hyperinflation
Phillip Cagan’s definition (1956), the one most economists use: a hyperinflation begins in the month prices rise 50% or more and ends when the monthly rate falls below 50% and stays there for at least a year. 50% a month is about 13,000% a year. The archive holds 20 hyperinflations and one contrast case, Turkey 1990–2005: decades of high inflation, never 50% in a month.
Worst month
The highest price rise in a single month, from the reference table of Hanke & Krus (World Hyperinflations, 2012) unless a case says otherwise. Never an annual rate: mixing the two makes cases impossible to compare. The exceptions are named on their pages: Venezuela (National Assembly estimate) and Lebanon (an implied rate, inferred by Steve Hanke from the black-market exchange rate).
Doubling time and dates
“For prices to double” is the number of days (or hours) prices took to double at the worst month’s pace (Hanke & Krus). The years in a case’s title cover the wider crisis; “above 50% a month” gives the months of the hyperinflation itself.
The curves
- How many units of the currency one US dollar bought, on a logarithmic scale and a true time axis.
- When a currency was redenominated, later values are converted back into the original unit, so removing zeros never looks like a recovery. The note under each curve says so.
- Many historical series exist only as scattered figures. Curves built from them are marked approximate: they show the shape, not exact values. The figures to quote are in the text, each with its source. Where no trustworthy series exists (Angola, the Philippines, Bolivia, Soviet Russia), there is no curve rather than a guess.
- “Worth ≈ $X that month” under a banknote divides its face value by that month’s average rate, and is shown only where the series is not approximate. Within a month of hyperinflation the rate could move several times over.
Banknotes and histories
Each banknote label is read off the note: denomination and the date printed on it. Each history is written from a knowledge base where every figure carries its source; anything that could not be verified is left out of the page.
Data for reuse, and for language models
Every case has a JSON file (figures, timeline, banknotes, series, sources) and a CSV of its series; all.json holds every case. llms.txt describes the site for AI assistants. Please cite the case page.
Found an error?
Historical figures differ between sources and we will have made mistakes. Open an issue on GitHub with the page, the figure and your source.
Main sources
- Hanke, S. H. & Krus, N. (2012), World Hyperinflations, Cato Institute Working Paper no. 8: episodes, worst months, doubling times.
- Cagan, P. (1956), “The Monetary Dynamics of Hyperinflation”, in M. Friedman (ed.), Studies in the Quantity Theory of Money.
- Hanke, S. H. (2020), “Lebanon Hyperinflates”, Cato Institute.
- Wikipedia articles on each currency and crisis, cited on each case with the date they were read.
- Fergusson, A. (1975), When Money Dies; Bresciani-Turroni, C. (1931, English translation 1937), The Economics of Inflation.
Disclaimer
- This site is educational. It is not financial, investment, legal or tax advice, and nothing on it predicts what any currency will do.
- Figures are given as reported by the cited sources, which sometimes disagree; we pick one, name it, and note serious disagreements. Provided as is, without warranty (MIT licence).
- The banknotes are historical items shown for study. They are not for sale here, and almost all of them stopped being money long ago.
- Privacy: no account, no cookies, no analytics. Fonts load from Google Fonts, which sees your IP address like any web request.