What is interest rate?

An interest rate is the cost of borrowing money, expressed as a percentage of the principal charged per period. Interest rates set by the Federal Reserve cascade through the financial system — affecting mortgage rates, credit card APRs, auto loans, and savings account yields. When rates rise to combat inflation, households with variable-rate debt face payment increases when their rates reset while new borrowers face higher costs, creating the financial squeeze the American Distress Index tracks.

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Key facts

  • The federal funds rate — the rate at which banks lend to each other overnight — is the Federal Reserve's primary policy tool; the Fed raised it from near zero starting in March 2022 to fight inflation.
  • Mortgage rates are loosely tied to the 10-year Treasury yield, not directly to the federal funds rate — 30-year fixed mortgage rates averaged about 3% in 2021; at 6.5%, the principal-and-interest payment on the same loan is about 50% higher.
  • The average interest rate on credit card accounts at commercial banks was 21.19% in Q3 2026, according to the Board of Governors of the Federal Reserve System. That average counts accounts that pay no interest, so it is not the rate people carrying a balance pay.
  • The 'rate lock trap' discourages existing mortgage holders with low rates from moving or refinancing, though they can access equity with a separate home equity loan without replacing their existing first mortgage.
  • The ADI captures interest rate effects through its Debt Burden domain — higher rates raise the household debt service ratio, claiming a larger share of household income.

Related data

How Do Interest Rates Work?

Interest rates are the price of borrowing money. They exist at multiple levels of the financial system:

  • Federal funds rate: The rate banks charge each other for overnight loans. Set by the Federal Reserve's Federal Open Market Committee (FOMC) as monetary policy. This is the 'base rate' from which other rates derive.
  • Prime rate: The rate banks charge their most creditworthy customers. Typically the federal funds rate plus 3 percentage points. Credit cards, HELOCs, and some adjustable-rate mortgages are tied to prime.
  • Treasury yields: The return on U.S. government bonds. The 10-year Treasury yield is the benchmark for mortgage rates. The 2-year yield is sensitive to Fed policy expectations.
  • Consumer rates: What households actually pay on mortgages, auto loans, credit cards and personal loans. These add risk premiums to the base rate, which is why credit cards cost the most: the average rate on credit card accounts at commercial banks was 21.19% in Q3 2026, according to the Federal Reserve.

How Interest Rates Affect Household Finances

Interest rate changes transmit through household budgets via several channels:

  • Mortgage payments: A 30-year fixed mortgage at 3% on $350,000 costs $1,476/month. At 7%, the same loan costs $2,329/month — a $853 increase (58%). This is why housing affordability collapsed despite stable home prices in some markets.
  • Credit card debt: At credit card rates, a minimum payment barely covers the interest, so a balance paid at the minimum can take decades to clear. See minimum payment for the math.
  • Adjustable-rate mortgages: Borrowers whose adjustable-rate mortgage started at a low rate can face a much higher payment when the rate resets.
  • Auto loans: Higher loan rates on top of higher vehicle prices push monthly car payments up.
  • Savings yield: The one positive: when rates rise, savings accounts pay more too. But households with depleted savings cannot benefit from higher yields.

The Rate Cycle and Financial Distress

Interest rate cycles have a delayed but powerful effect on household financial distress:

  1. Rate hikes begin: Variable-rate debt becomes more expensive when its rates reset. New borrowing costs rise.
  2. Lag period (6-18 months): Households absorb higher costs by drawing down savings, reducing discretionary spending, and taking on more debt.
  3. Buffer erosion: The personal saving rate falls and the household debt service ratio climbs — the ADI's Safety Net & Buffer and Debt Burden domains capture this phase. A rise in 401(k) hardship withdrawals is contextual evidence of the same buffer depletion.
  4. Delinquency wave: When buffers are exhausted, households begin missing payments — first credit cards and auto loans, then mortgages. The ADI's Delinquency domain captures this phase.
  5. Rate cuts begin: The Fed eventually cuts rates — but by then, damage is done. It takes 2-3 years for lower rates to fully transmit to household finances.

Interest Rates and the American Distress Index

The ADI includes the household debt service ratio in the Debt Burden domain and the personal saving rate in the Safety Net & Buffer domain. The personal saving rate measures income left after spending, not the size of accumulated savings. Rising credit card APRs are contextual evidence of the consumer-facing cost of revolving debt.

State-by-state differences

The Fed sets a national policy target, and banks and markets set household loan rates. The impact of those rates varies by state, based on housing costs, state usury laws and local economic conditions. Some states cap certain consumer lending rates.

StateKey difference
CaliforniaHigh home prices amplify the mortgage rate effect — a 1% rate increase on a $750,000 California mortgage costs $500+/month more than on a $250,000 national median home. State usury limit of 10% for non-exempt lenders.
TexasHome equity lending constitutionally limited (80% LTV max, 2% fee cap). This protects homeowners from overleveraging but limits access to home equity as a financial buffer during high-rate periods.
New YorkCivil usury cap of 16% and criminal usury cap of 25% for non-bank lenders. However, national bank preemption (Marquette National Bank v. First of Omaha) means credit cards issued by out-of-state banks can charge higher rates.
South DakotaNo usury cap — this is why many major credit card issuers (Citibank, Wells Fargo) are headquartered in South Dakota, enabling them to charge rates that would violate usury laws in other states.
ArkansasConstitutional usury limit of 17% (Amendment 89, passed 2010). One of the few states where the rate cap has practical teeth for consumer lending, though federal preemption allows national banks to override.

Questions about interest rate

What are current interest rates?

The average credit card APR at commercial banks was 21.19% in Q3 2026, according to the Federal Reserve. The Fed publishes its current federal funds target range after each policy meeting, and Freddie Mac publishes weekly 30-year mortgage rates.

How do interest rates affect mortgage payments?

Every 1 percentage point increase in mortgage rates raises the monthly payment on a $350,000 loan by approximately $200-250. Going from 3% to 7% on a $350,000 loan over 30 years raises the monthly principal and interest payment by about 58%, from $1,476 to $2,329, making the same home far less affordable for new buyers.

Why does the Federal Reserve raise interest rates?

The Fed raises rates to slow inflation by making borrowing more expensive, which reduces consumer spending and business investment. The trade-off: higher rates slow the economy and can trigger job losses. The Fed's dual mandate is maximum employment AND stable prices (2% inflation target).

When will interest rates come down?

Rate cuts depend on inflation progress and labor market conditions. The Fed signals its intentions through dot plots and FOMC meeting minutes. The Fed says its decisions depend on incoming economic data. Mortgage rates may not fully follow — they depend on Treasury yields and the 'term premium.'

How do interest rates connect to the American Distress Index?

The ADI captures interest rate effects through the household debt service ratio in its Debt Burden domain and the personal saving rate in its Safety Net & Buffer domain. Higher rates increase payment burdens, squeeze refinancing options, and tighten credit — creating the conditions for delinquency cascades.

Related terms

  • Federal Funds RateThe interest rate banks charge each other for overnight loans, which the Federal Reserve steers into a target range it sets.
  • Yield CurveA graph showing interest rates on debt with different maturities.
  • InflationA rise in the overall level of prices over time.
  • APR (Annual Percentage Rate)The annualized cost of credit, including interest and certain fees, used to compare borrowing offers.
  • Adjustable-Rate Mortgage (ARM)A mortgage whose interest rate changes on scheduled adjustment dates under the loan agreement.
  • Debt Service RatioRequired minimum debt payments as a percentage of disposable personal income. 11.11% in Q2 2026, about one in every nine dollars of after-tax income.
  • RecessionA significant, economy-wide decline in activity lasting more than a few months, as dated by the National Bureau of Economic Research's committee.
  • Cost of LivingHow much money it takes to cover basic expenses, such as housing, food and transportation, in a given place at a given time.

Sources and method

We write with assistance from AI tools. Figures come from the data and sources named on this page.