How Inflation Works

In 1921, a cup of coffee in Weimar Germany cost 1 mark. By November 1923, it cost 100 billion marks. By the time you’d finished drinking it, the price had risen again. Workers were paid twice daily so they could shop before the afternoon price increases. People burned banknotes for heat because firewood cost more. This is what happens when inflation is left completely unchecked. Understanding why it happens begins with something more mundane: why things cost what they do in the first place.

The short answer

Inflation is the gradual loss of your money’s purchasing power. A dollar today buys less than a dollar did ten years ago. Central banks try to keep inflation around 2% per year, because a little inflation encourages spending and investment, while too much erodes savings and creates uncertainty.

The full picture

What inflation actually means

When economists say inflation is “2%”, they mean prices are 2% higher than last year on average. That doesn’t mean everything gets more expensive at the same rate. Healthcare and college tuition have surged far ahead of inflation, while tech gadgets have actually gotten cheaper.

The real pain shows up in what your money can buy. $1 in 1970 is worth about $8 today. A $20,000 car in 1990 would cost roughly $45,000 adjusted for inflation. Your savings lose value silently, every single year.

How it’s measured

Two indexes dominate the conversation. The Consumer Price Index (CPI) tracks prices of a basket of goods that typical households buy, everything from gasoline to rent to cereal. It’s the one you hear about in news headlines.

The Personal Consumption Expenditures (PCE) is broader and gets more respect from the Federal Reserve. It accounts for what people actually spend money on, including healthcare and investment fees. When the Fed says it targets 2% inflation, it’s usually referring to PCE.

Both have flaws. They don’t capture housing costs accurately (they use rents, not home prices), and they struggle with quality improvements. A laptop costs $1,000, but it’s infinitely more powerful than a $1,000 machine from 2005. That gets counted as “inflation” even though you’re getting way more value.

Demand-pull vs cost-push

Economists split inflation into two types. Demand-pull happens when too many people want too few goods. Think Black Friday: everyone wants the same discounted TV, so sellers raise prices. This typically happens when the economy is booming and unemployment is low.

Cost-push occurs when production gets more expensive and companies pass those costs to consumers. When oil prices spike, everything transported becomes more expensive. When a pandemic disrupts supply chains, raw materials get scarce and prices rise. This type is harder for central banks to fix, because raising interest rates doesn’t unblock a shipping container stuck in a port.

The money supply connection

The quantity theory of money states that when a central bank prints more money, prices eventually rise. The logic is straightforward: more money chasing the same goods equals higher prices. It’s not a perfect relationship, but it explains why massive money printing often leads to inflation.

Between 2020 and 2022, the U.S. M2 money supply jumped about 40%, according to Federal Reserve data. That wasn’t the only reason inflation surged, but it was a significant factor. When governments inject trillions into the economy through stimulus and low-interest loans, that money has to go somewhere.

How central banks respond

The primary tool is the interest rate. When inflation runs hot, central banks raise rates. Higher borrowing costs discourage spending and investment. Businesses hold off on expansion. Consumers delay big purchases like homes and cars. Demand cools, and prices stabilize.

The Federal Reserve’s dual mandate is maximum employment and stable prices. It’s a balancing act. Raise rates too aggressively and you trigger a recession. Keep them too low for too long and inflation spirals.

Central banks also adjust the money supply directly through open market operations, buying or selling government bonds to inject or drain liquidity from the banking system. In extreme cases, they use quantitative tightening, essentially reversing the money printing of previous years.

Hyperinflation: when it spirals

Most inflation is manageable. Hyperinflation is something else entirely. It’s defined as prices rising more than 50% per month, which compounds catastrophically.

Weimar Germany (1921–1923) is the classic example. After World War I, Germany’s government printed money to pay war reparations and domestic debts. At its peak in November 1923, prices doubled every few days. People burned money for heating because it was cheaper than buying wood. Workers were paid twice daily so they could spend wages before they became worthless.

Zimbabwe (2000s) saw inflation reach 89.7 sextillion percent in November 2008, according to the Cato Institute’s Troubled Currencies Project. The central bank printed 100-trillion-dollar notes. People became millionaires overnight, but those millions couldn’t buy a loaf of bread. The government eventually abandoned its currency entirely in 2009.

Venezuela has experienced hyperinflation exceeding 1,000% annually from 2017 onward, peaking at over 1,000,000% in 2018 according to IMF estimates. Sanctions, oil production collapse, and currency mismanagement created a perfect storm. Scarcity became the norm, and the informal economy (bartering, using foreign currency) replaced normal commerce.

What unites these cases? Reckless money printing, political instability, and a loss of faith in the government’s ability to manage the economy.

Why 2% is considered healthy

Most central banks target around 2% inflation. Why that number? It’s high enough to avoid the dangers of deflation, but low enough to preserve purchasing power reasonably well.

The logic: a little inflation encourages spending. If you expect prices to rise, you buy now rather than later. That keeps the economy humming. It also gives central banks room to cut interest rates during downturns, providing a buffer before hitting the zero lower bound.

Deflation sounds good on paper. Prices falling means your money buys more. But it creates a vicious cycle: consumers delay purchases hoping prices will drop further, businesses lose revenue, workers get laid off, and the economy contracts. Japan’s “lost decade” in the 1990s showed how hard it is to escape deflation once it takes hold.

The savers vs debtors divide

Inflation is not neutral. It redistributes wealth from savers to borrowers.

If you have $10,000 in a savings account earning 0.5% interest, but inflation is 3%, your real return is -2.5%. Your money is losing purchasing power while appearing to grow on paper. This is the dark side of compound interest: compounding at a rate below inflation means quietly going backward.

Meanwhile, someone who borrowed $200,000 for a mortgage at 3% interest is effectively paying back less in real terms over time. Their debt becomes easier to service as wages (theoretically) rise with inflation. This is why inflation is sometimes called a “hidden tax” on savers and a windfall for debtors.

This dynamic matters for policy. Generous stimulus and low interest rates help debtors and hurt savers. Retirees on fixed pensions get squeezed. Young people with mortgages benefit.

Deflation: the other danger

While high inflation grabs headlines, deflation can be worse. When prices fall consistently, consumers stop spending waiting for better deals. Businesses see revenues drop. They cut jobs. Unemployment rises. Debt becomes more expensive in real terms even as interest rates fall to zero.

The Great Depression in the 1930s featured severe deflation. U.S. prices fell about 10% per year at the worst. The Federal Reserve’s failure to prevent the money supply from contracting made everything worse.

Japan’s experience since the 1990s shows how deflation becomes self-reinforcing. Consumers expect prices to fall, so they spend less. Companies can’t raise prices, so they freeze wages. The economy stalls, and conventional monetary policy loses its effectiveness.

Why your intuition about inflation is often wrong

Most people track inflation by remembering what things used to cost. And this works reasonably well for groceries and gas, which you buy regularly. But it fails badly for things you buy infrequently, and it creates some strange distortions in how we perceive the economy.

Shrinkflation is when companies keep prices the same but reduce the size or quantity of the product. A bag of chips that was 400g becomes 340g at the same price, technically deflation in quantity, but experienced as a price increase. Statisticians who measure CPI account for this (it counts as an effective price increase), but consumers often don’t notice until they get the new pack home.

Hedonic adjustment is one of the more controversial aspects of how inflation is measured. When a laptop that cost $1,000 in 2010 costs $1,000 today but is dramatically more powerful, statisticians apply a “hedonic quality adjustment” that counts the improved product as a price decrease. From one perspective, this is correct. You’re getting more for the same money. From another, it understates what many households actually experience, because they need the current laptop, not the 2010 one.

The categories that have seen the most persistent inflation since 2000 are exactly the ones where government is heavily involved: healthcare, higher education, and housing. The categories that have seen deflation or modest inflation are mostly manufactured goods: electronics, clothing, furniture. This isn’t coincidence. Competition and global supply chains compress goods prices. Markets with high regulatory barriers or artificial constraints on supply see the opposite.

Understanding which kind of inflation you’re experiencing matters for the choices you make: whether to lock in prices now, whether to take on debt, and whether the cost-of-living adjustments in your contract actually keep pace with the costs that matter to you.

Why it matters

Inflation isn’t just an abstract number on a dashboard. It determines whether your savings keep their value, whether your salary keeps pace with the cost of living, and whether the economy is creating jobs or slipping into recession.

For everyday decisions, understanding inflation helps you time major purchases, negotiate salaries, and think about where to keep your money. For investors, inflation dictates bond yields, stock valuations, and the attractiveness of alternatives like real estate or commodities.

Central banks walk a narrow path. Too much inflation erodes trust and living standards. Too little (or deflation) strangles growth and employment. The choices they make affect your mortgage rate, your job prospects, and the prices at the grocery store.

Common misconceptions

“Inflation means prices are rising”: Not exactly. Inflation means prices are rising relative to what they were, but relative to wages and other costs, you might actually be worse off even with moderate inflation. The real measure is purchasing power, not the absolute price level.

“The government can just control inflation”: Partly true, but it’s not simple. The Fed influences demand through interest rates, but supply shocks like oil crises or pandemics are largely outside their control. Coordination between fiscal policy (government spending) and monetary policy (central bank actions) matters enormously.

“Inflation is always bad”: A small, predictable amount of inflation is considered healthy. It greases the wheels of the economy, encourages spending over hoarding, and gives central banks flexibility to respond to downturns. The problem is runaway inflation, not inflation itself.