What Causes Inflation and Should I Worry About It?

Inflation has become central to the American zeitgeist in 2021 in a way that it hadn’t been for decades. Google searches are up. Supply chain issues feature into popular Instagram posts. The satire website The Onion warned in a recent headline that “higher prices may force Americans to eat reasonable portions on Thanksgiving.”

Even as inflation hits its highest level since 1982 and inserts itself as a topic of popular discussion, trying to understand it can be a mind-bending task. Some people who have studied markets and the economy for years often do not know the ins and outs of how inflation is calculated. Its aftereffects on society — from who wins and who loses to whether it is good or bad news — are nuanced.

Here’s a guide to help explain what inflation is, including how it is measured and what it means for your economic security and savings.

What is inflation?

Inflation is a loss of purchasing power over time: It means your dollar will not go as far tomorrow as it did today.

Inflation is typically expressed as the annual change in prices for a basket of goods and services. In the United States, there are two main inflation gauges.

One, the Consumer Price Index or C.P.I., measures the cost of things urban consumers buy out of pocket. The other, the Personal Consumption Expenditures index, or P.C.E., is released at more of a lag and measures things people consume, including things they do not pay for directly — notably health care, which insurance and government benefits help to cover. The two indexes are also built slightly differently.

The Federal Reserve, America’s central bank and the institution in charge of keeping prices from increasing too rapidly, targets 2 percent annual increases in the P.C.E. index on average over time. A little bit of consumer price inflation is generally viewed as desirable, in part because it gives companies room to adjust to a changing economy — one where labor and commodities might cost more — without being forced out of business.

What causes inflation?

In the short term, high inflation can be the result of a hot economy — one in which people have a lot of surplus cash or are accessing a lot of credit and want to spend. If consumers are buying goods and services eagerly enough, businesses may need to raise prices because they lack adequate supply. Or companies may choose to charge more because they realize they can raise prices and improve their profits without losing customers.

But inflation can — and often does — rise and fall based on developments that have little to do with economic conditions. Limited oil production can make gas expensive. Supply chain problems can keep goods in short supply, pushing up prices.

The inflationary burst America has experienced this year has been driven partly by quirks and partly by demand.

On the quirk side, the coronavirus has caused factories to shut down and has clogged shipping routes, helping to limit the supply of cars and couches and pushing prices higher. Airfares and rates for hotel rooms have rebounded after dropping in the depths of the pandemic. Gas prices have also contributed to heady gains recently.

But it is also the case that consumers, who collectively built up big savings thanks to months in lockdown and repeated government stimulus checks, are spending robustly and their demand is driving part of inflation. They are continuing to buy even as costs for exercise equipment or outdoor furniture rise, and they are shouldering increases in rent and home prices. The indefatigable shopping is helping to keep price increases brisk.

Where is inflation headed and should I be worried?

Officials say they do not yet see evidence that rapid inflation is turning into a permanent feature of the economic landscape, even as prices rise very quickly: The C.P.I. measure rose by 6.8 percent in the year through November, the fastest pace since 1982.

There are plenty of reasons to believe that the price burst will fade. Much of the increase this year owes to shortages of goods — from bicycles to cars and beds — that are likely to eventually ease as companies figure out how to produce and transport what people want to buy in a pandemic-altered economy. Many households also have built up savings, in part because of repeated stimulus payments, but they eventually could exhaust those.

Plus, before the pandemic, aging demographics and high inequality in income and wealth had combined to drag inflation steadily lower for years as people preferred to save money instead of spending it, and those basic economic building blocks haven’t changed.

But there are concerning signs that inflation is becoming stickier, meaning that it might last rather than fading with time. Rents have picked up sharply as home prices have risen and would-be buyers have found themselves locked out of ownership. Consumers are slowly starting to anticipate higher prices, though long-term inflation expectations have yet to jump drastically higher.

In the longer term, the (sometimes contested) theory goes, high inflation can become entrenched if workers begin to expect it and can successfully negotiate wage increases to cover their climbing costs. Companies, facing higher labor bills, may manage to pass the costs onto consumers — and voilà, you have a situation where pay and prices push one another steadily upward.

Is inflation bad?

Whether inflation is “bad” depends on the circumstances.

Most everyone agrees that super fast price increases — often called hyperinflation — spell trouble. They destabilize political systems, turn middle-class workers into paupers overnight, and make it impossible for businesses to plan. Weimar Germany, where hyperinflation helped to usher Adolf Hitler into power, is often cited as a case in point.

Moderate price gains, even ones a bit above the Fed’s official goal, are a topic of more-serious debate. Slightly higher inflation can be good for people who owe money at fixed interest rates. If I sell coconuts for $1 and owe my bank $200 today, but next year I am suddenly able to charge $1.05 for my coconuts, my debt becomes easier for me to pay back: Now I only have to sell a little bit over 190 coconuts plus interest.

But inflation can be tough for lenders. The bank to whom I owe my $200 is obviously not happy to get 190 coconuts worth of money instead of 200 coconuts worth. While politicians and the public rarely cry for bankers, the same is true for people with savings that bear low interest: Their holdings will not go as far. Inflation can be especially tough for people on fixed incomes, like students and many retirees.

For workers taking home paychecks, whether inflation is a good or bad thing hinges on what happens with wages. If a worker’s pay goes up faster than prices increase, they can still find themselves better off in a high-inflation environment.

Wages are growing quickly right now, especially for lower earners, but some measures suggest the growth is not keeping pace with inflation as it picks up steeply. Still, many households are also receiving transfers from the government — including an expanded Child Tax Credit — which could keep some families’ financial situations from deteriorating.

How does inflation affect the poor?

High or unpredictable inflation that isn’t outmatched by wage gains can be especially hard to shoulder for poor people, simply because they have less wiggle room.

Poor households spend a bigger chunk of their budgets on necessities — food, housing and especially gas, which is often a contributor to bouts of high inflation — and less on discretionary expenditures. If rich households face high inflation and their wages do not keep up, they may have to cut back on vacations or dining out. A poor family may be forced to cut back on essentials, like food.

“For lower income households, price increases eat up more of their budget,” said Laura Rosner-Warburton, a senior economist at MacroPolicy Perspectives, pointing out that some research suggests that poor people may even end up paying comparatively more for the same products. That may be partly because they lack the free cash to take advantage of temporary discounts.

Around the world, poor people historically have reported greater concern around inflation, and that is also the case in the United States in the current episode.

How does inflation affect the stock market?

Really high inflation typically spells trouble for stocks, said Aswath Damodaran, who teaches corporate finance and valuation at New York University’s Stern School of Business. Financial assets in general have historically fared badly during inflation booms, Mr. Damodaran said, while real assets like houses have better held their value.

The reason is simple.

“You need to make higher returns to break even,” he explained. While it might have been attractive to invest money for a 3 percent annual payback before an inflationary burst, once inflation has taken off to 4 percent, your investment would actually be declining in terms of real-world purchasing power.

Plus, inflation can be tough on the underlying business. Companies that lack pricing power — meaning that they cannot easily pass costs on to customers — suffer the worst, because they are forced to absorb input cost increases by taking a hit to their profit margin.

High inflation can also spur the Federal Reserve to increase interest rates as it tries to cool off the economy and slow demand. If the central bank does so drastically, it could even plunge the economy into a recession, which would also be bad for stocks — along with everyone else.

“The worse inflation is, the more severe the economic shutdown has to be to break the back of inflation,” Mr. Damodaran said.