What Is Inflation

The word “inflation” is the most contested term in monetary economics, and the contest is not academic. The definition you accept determines what you blame for rising prices, what policies you support, and whether you can recognise the cause when it is happening to you. This page sets out the two competing definitions, the arithmetic that connects money supply to prices, and the empirical record that decides between them.

Two definitions, and why it matters

There are two definitions of “inflation” in active circulation. They do not point at the same thing.

Definition A (classical / Austrian). Inflation IS an increase in the quantity of money and credit. Rising prices are a consequence of inflation, not the inflation itself. Ludwig von Mises in The Theory of Money and Credit (1912), Mises Institute edition, is direct: inflation means an increase in the quantity of money in circulation; what people now call “inflation” is the result of inflation, namely the rising tendency of prices and wages, and the popular definition leaves no word for the cause. Murray Rothbard reinforces the point in What Has Government Done to Our Money? (1963), Mises Institute.

Definition B (modern / popular). Inflation IS the rate of change of a consumer price index. Money supply is one factor among many (others include “supply chains”, “expectations”, “wage-price spirals”, “corporate margins”). Under this definition the cause of rising prices is an open question to be answered by regression rather than by accounting identity.

The site uses Definition A because it preserves the causal arrow. If you call the symptom “inflation” and the cause something else, you have rhetorically severed the link between the central bank’s printing press and the price at the supermarket. That severance is what the post 1971 monetary regime requires in order to keep operating without political consequences. We are not willing to do the regime that favour. When the rest of the site says “inflation rose 8% in 2022”, we use the popular shorthand for readability; when we say “the inflation of 2020 to 2022 caused the price rises of 2021 to 2024”, we mean the monetary expansion caused the price rises. The arrow is the point.

The arithmetic identity: MV = PQ

Irving Fisher’s The Purchasing Power of Money (1911), Liberty Fund online edition, formalised the equation of exchange:

M × V = P × Q

Where:

Symbol	Meaning
M	Quantity of money in circulation
V	Velocity of money (turnover rate per unit per period)
P	General price level
Q	Real output (real quantity of goods and services traded)

The identity is true by construction. The left side is total spending; the right side is total nominal value of goods and services bought. They are the same number written two ways. There is no “if” about it.

The behavioural content sits in the question: which side is doing the work when one side rises? If M rises 40% over two years and V and Q are roughly stable, then P must rise by roughly 40% over the same window. That is not a theory; it is the equation rearranged.

Fisher’s empirical work concluded that V was relatively stable in normal times and that Q grew at a steady rate tied to productivity and population. Sustained changes in P were therefore traceable to sustained changes in M. This conclusion was reinforced by Friedman and Schwartz in A Monetary History of the United States, 1867 to 1960 (1963), and by Bordo, Rockoff, and Schwartz’s later work on the gold standard era.

V can shift abruptly during financial panics (1930 to 1933, briefly 2008 to 2009). Q shifts in wars and pandemics. These are episodes, not the secular trend. The secular trend over decades is dominated by M. This is acknowledged even by the Bank of England’s 2014 paper Money creation in the modern economy.

Why supply shocks alone do not produce sustained inflation

A supply shock (an oil embargo, a war, a drought, a pandemic) reduces Q in some sector. With M and V unchanged, the relative price of the affected good rises and the relative prices of other goods fall. The general price level P shifts only marginally, by the share of the shocked good in the basket times the size of the shock. To convert a one-time relative-price shift into a sustained rise in the general level, M must expand. Otherwise households, having spent more on the shocked good, spend less elsewhere, and other prices fall to clear the market.

The 1973 OPEC embargo is the textbook case. Oil quadrupled. Energy was around 8% of US household spending in 1973; a quadrupling of one eighth of the basket should produce a one-time price-level shift of roughly 24%, then dissipate. Instead US CPI rose roughly 100% from 1973 to 1981 (FRED CPIAUCSL) while M2 also roughly doubled (FRED M2SL). Inflation was sustained because the Federal Reserve under Burns and Miller validated the shock by expanding the money supply. Bordo’s NBER working paper 23211 confirms the accommodation pattern.

The mirror test seals the argument. The 1986 oil price collapse cut crude by more than half within months. Under the supply-shock theory this should have produced a deflationary collapse comparable in magnitude to the 1973 surge. CPI rose 1.9% in 1986 and 3.6% in 1987. The Federal Reserve continued to expand M, so P continued upward. Q changed; M continued; P followed M.

Supply shocks change relative prices. Money expansion changes the general price level. The two phenomena are routinely confused in the press because they often coincide, but the arithmetic and the empirical record both separate them cleanly.

”Greedflation” debunked

The 2021 to 2024 price wave was attributed in mainstream press and political speeches to “corporate greed” or “greedflation”. The argument: corporations raised margins, and that raised prices.

This argument fails on two grounds.

First, motive is constant. Corporations have wanted margins in every year since corporations existed. If corporate desire for profit caused inflation, inflation would be a constant feature of every economy with corporations, which it is not. The 19th century gold standard era had corporations with profit motives and produced near zero secular inflation across a century. Constants cannot explain variables.

Second, the timing fits M, not motive. US M2 expanded from approximately $15.4 trillion in February 2020 to approximately $21.7 trillion in April 2022, a ~41% expansion in 26 months (FRED M2SL). CPI began accelerating in early 2021 and peaked at 9.1% year-on-year in June 2022 (FRED CPIAUCSL). The lag from monetary expansion to peak CPI was approximately 18 to 24 months, consistent with the money-to-prices lag documented by Friedman.

Corporate margins did rise during 2021 to 2022. This is not the cause; it is the mechanism by which the new money entered the price system. When M expands, the new money is spent. Sellers, facing willing buyers at higher prices, raise prices and pocket the spread until input costs catch up. This is what monetary expansion looks like at the firm level. The Kansas City Fed’s 2023 review Have Profits Contributed More to Inflation? found that the persistence and breadth of the inflation are not consistent with a margin-driven story. The breadth is consistent with a money-supply story.

”Putin’s price hike” and “supply chains”

Two further post-hoc framings appeared in 2021 to 2023: that inflation was caused by Russia’s February 2022 invasion of Ukraine (“Putin’s price hike”), and that it was caused by COVID-era supply chain disruption.

Both fail the timing test. US CPI year-on-year crossed 2% in March 2021, 4% in April 2021, 5% in May 2021, and 7% by December 2021 (FRED CPIAUCSL). Russia invaded Ukraine in February 2022. Inflation had already been running at 7%+ for two months before the invasion and had been above the Fed’s 2% target for the preceding eleven months. The invasion is post hoc; the inflation is ante.

Supply chains were strained from mid 2020 onward, but the strain affected specific goods (semiconductors, shipping, lumber) rather than the broad basket. The 2021 to 2024 price rise was broad, persisting after supply chains normalised in late 2022. The breadth and persistence point to M, not to bottlenecks. These framings are political: they place the cause outside the central bank and the legislature. The arithmetic places it inside.

Lived experience versus CPI

Households in the US, UK, and eurozone routinely report sustained 5 to 10% annual increases in essential spending (food, rent, energy, insurance, healthcare) while the headline CPI prints 2 to 3%. The gap is not perception error; it is methodology.

Headline CPI underweights essentials in two ways. First, the basket is constructed for an average household whose spending is distributed across many categories the median household barely touches (high-end durable goods, discretionary services). Second, methodological adjustments since the 1980s (substitution, hedonic adjustment, owners-equivalent rent in place of housing prices, geometric weighting) systematically reduce the reported number versus pre 1980 methodology. We treat this in detail in 03-mechanisms/03-cpi-manipulation-and-measurement.md. John Williams’s Shadowstats reconstruction of pre 1980 methodology routinely shows headline US inflation 4 to 7 percentage points higher than the official series.

The other half of the gap is asset-price inflation, which the CPI excludes by construction.

Asset-price inflation versus consumer-price inflation

Both are inflation under Definition A. Both are the consequence of money expansion. CPI captures only the consumer-goods channel. New money does not flow evenly into all prices; it flows first to those who receive it earliest, who are typically banks, large corporations, and asset holders. This is the Cantillon effect (treated in 03-mechanisms/02-cantillon-effect.md).

The empirical signature of Cantillon-mediated monetary expansion is that asset prices (real estate, equities, fine art, collectibles) rise faster than consumer prices. The S&P 500 rose from approximately 740 in March 2009 to approximately 4800 in January 2022, a 6.5x increase in 13 years, against a CPI rise of approximately 35% in the same period. US median home prices roughly tripled over the same window while official CPI shelter rose far less.

Households without assets experience this as wage stagnation against rising rents. Households with assets experience it as rising net worth. Both are responding to the same M expansion; the distributional consequence is the wealth gap that has widened systematically since 1971. The CPI looks “tame” because the inflation has been routed through the asset channel, which the CPI does not measure. To see the full inflation, you must look at M2 growth, asset prices, and CPI together.

Disinflation, deflation, inflation

Three terms get conflated in press coverage:

Term	Meaning
Inflation	Price level rising (P trending up)
Disinflation	Inflation slowing (P still rising, but rate falling)
Deflation	Price level falling (P trending down)

The 2023 to 2024 episode of US CPI declining from 9.1% to 3% was disinflation, not deflation. Prices were still rising; they were rising more slowly. The price level itself remained at the 2022 peak and continued upward.

Deflation in the modern fiat era is rare and brief, occurring only in panic conditions where credit collapses faster than central banks can re-inflate (1930 to 1933 in the US, briefly 2008 to 2009, briefly Japan in episodes). Under the classical gold standard, by contrast, mild deflation was normal and healthy: as productivity grew faster than gold supply, prices fell at roughly 0.5 to 1% per year, and real wages rose silently. UK CPI in 1913 was lower than UK CPI in 1815 (Bank of England Millennium of Macroeconomic Data). A worker holding a sovereign in 1815 could spend it in 1913 and buy more, not less.

This refutes the modern claim that “deflation is dangerous”. A century of mild productivity-driven deflation produced the industrial revolution, the railway boom, electrification, and rising real living standards across all classes. Deflation is dangerous only inside a debt-based monetary system where falling prices raise the real burden of debts. The fiat-credit system creates the debt structure that makes deflation dangerous; deflation is not dangerous in itself.

The 2 percent target

Most major central banks today target 2% annual CPI inflation. The number is not derived from theory. It was picked.

The 2% target originated at the Reserve Bank of New Zealand in 1989. Don Brash, then RBNZ governor, has described the choice in interviews and in his memoir Incredible Luck (2014). The figure was drawn from a televised interview given by Roger Douglas, then Finance Minister, who mentioned a target range of 0 to 1%, which was negotiated up to 0 to 2% in the Policy Targets Agreement of March 1990. There was no econometric study, no theoretical derivation, no welfare optimisation. Mike Reddell, who was at the RBNZ during this period, has written that the number was essentially arbitrary, Croaking Cassandra.

Other central banks adopted the 2% number through institutional copying through the 1990s: Bank of Canada (1991), Bank of England (1992), Sweden’s Riksbank (1993), ECB (formally 2003, “below but close to 2%”), Federal Reserve (formally 2012). The arbitrary New Zealand number became the global standard.

The compounded cost of a 2% target is non-trivial. At 2% per year, the price level doubles in 35 years. A retiree saving in cash over a 40 year working life loses ~55% of purchasing power to a perfectly-on-target central bank. A 0% target would have preserved that purchasing power. There is no published welfare analysis demonstrating that 2% is superior to 0%. The choice has been institutional, not analytical.

What “stable money” means

Stable money is not a Utopian aspiration; it is an empirical record. The classical gold standard era of 1815 to 1913 delivered roughly zero secular inflation across a century in the United Kingdom, the United States, and other gold-standard economies. The Bank of England’s Millennium of Macroeconomic Data records UK CPI in 1913 below UK CPI in 1815. US wholesale prices in 1913 were below US wholesale prices in 1815 (Historical Statistics of the United States, series E135).

Within that century, prices rose during wars (Napoleonic, Crimean, US Civil War) and fell back afterwards. The mean reversion is the property the gold standard delivered. The post 1971 fiat regime has no mean reversion; the price level is monotonically upward.

The comparison is the central empirical fact this site is built around:

Era	Approximate dates	Cumulative price change	Annualised rate
UK classical gold standard	1815 to 1913	~ -10% to flat	~ 0%
US classical gold standard	1815 to 1913	~ -25% to flat	~ -0.2%
US gold-exchange / Bretton Woods	1914 to 1971	~ +260%	~ 2.3%
US pure fiat	1971 to 2026	~ +700%+	~ 3.8%
UK pure fiat	1971 to 2026	~ +1500%+	~ 5.0%

Sources: Bank of England Millennium dataset, FRED CPIAUCSL, BLS CPI historical tables.

The popular claim that “we need 2% inflation for growth” must explain how the 19th century United Kingdom built the world’s largest industrial economy under near zero inflation. It cannot, because the claim is unsupported by the data. Growth and stable money coexisted for a century. They were not enemies. The framing that they are enemies is a post 1971 framing constructed to defend a post 1971 system.

Hidden taxes inside the inflation

Inflation operates as a tax in three layers, treated in detail in 03-mechanisms/04-taxation-as-second-extraction.md:

1. The inflation tax proper. Currency holdings depreciate by the inflation rate. A household holding $10,000 in cash for a year at 8% inflation has been taxed $800 in real purchasing power. The tax is paid silently, with no legislation and no vote.

2. Bracket creep. Income tax brackets denominated in nominal currency push earners into higher brackets as nominal incomes rise. The earner pays a higher real tax rate on unchanged real income.

3. Capital gains tax on nominal gains. An asset purchased for $100,000 and sold for $200,000 after 20 years of 5% inflation has roughly broken even in real terms; the tax authority treats the $100,000 nominal gain as taxable. The holder pays tax on inflation, not on real wealth created.

These three taxes compound the visible income, sales, and property taxes. State extraction from a median household in fiat economies is structurally higher than the headline tax rate suggests, because inflation is a parallel tax channel that does not appear on a tax return.

Hyperinflation is the same mechanism, amplified

Hyperinflation is not a separate phenomenon from ordinary inflation. It is the same mechanism (monetary expansion to monetise government deficits) with the brake removed. Triggers vary: Weimar Germany 1921 to 1923 (war reparations), Hungary 1945 to 1946 (war debts), Zimbabwe 2007 to 2009 (land reform and sanctions), Venezuela 2016 onward (oil collapse and populism), Argentina across the post war decades (chronic deficits), Turkey 2021 onward (political pressure on the central bank). Case studies are documented in 02-history/06-hyperinflation-cases.md.

The mechanism in every case is identical. The state cannot or will not balance its books. The central bank monetises the deficit. Money supply rises faster than output. Confidence in the currency erodes, V rises as people spend faster to avoid the depreciation, prices accelerate. At a critical threshold the population abandons the currency entirely.

The dollar is not in hyperinflation. It is on the same trajectory at a slower compounding rate, protected by reserve currency status, legal tender laws, and the absence of an alternative the population can coordinate on at scale. M2 has expanded approximately 28x since 1971; CPI has risen approximately 8x; the difference has been routed through asset prices and absorbed by foreign holders. The mechanism is the same as Weimar’s; the amplitude differs. Ordinary fiat inflation and hyperinflation sit on a single continuum, separated by the rate of expansion and the speed at which confidence breaks.

Summary

Inflation is monetary expansion. Rising prices are its consequence. The arithmetic identity MV = PQ ties the two together, and the empirical record across two centuries confirms the arithmetic. Supply shocks, corporate margins, wars, and supply chain disruptions are not causes of sustained inflation; they are either relative price effects or post-hoc political framings. The 19th century gold standard delivered a century of stable money and rising real wages without an inflation target, refuting the modern claim that 2% inflation is necessary for growth. The 2% target itself was picked arbitrarily in New Zealand in 1989 and copied institutionally. Hyperinflation is the same mechanism amplified.

The next sections of this knowledgebase examine the specific machinery: how money is created in a fiat-credit system, the Cantillon effect, CPI methodology, and the institutional history that delivered us to the present regime.