In economics, credit is the exchange of something valuable now for a promise to repay later. A lender hands over money or goods today; a borrower commits to return that value, usually with interest, on an agreed schedule. That simple trade sits underneath nearly every mortgage, car loan, credit card swipe, business line of credit, and government bond in a modern economy. With the federal funds rate at 3.50%–3.75% in early 2026 and the average credit card charging roughly 21% APR, the price of that trust varies enormously depending on who is borrowing and why.
The Parts of a Credit Transaction
Every credit arrangement has the same moving pieces. A creditor provides money or goods, and a debtor receives them. The amount handed over at the start is the principal. A repayment schedule, an interest rate, and a maturity date complete the deal. Those terms get written into a binding agreement, whether that’s a promissory note, a loan contract, or the fine print on a credit card application. The Uniform Commercial Code, which standardizes commercial transactions across most states, treats these agreements as enforceable obligations once both sides agree.1Legal Information Institute. Uniform Commercial Code 1-201 – General Definitions
The single biggest split within credit is whether the debt is secured or unsecured, because that determines what happens when a borrower stops paying. Secured debt is backed by collateral. A mortgage uses the home; an auto loan uses the car. If the borrower defaults, the lender can seize that asset. Unsecured debt has no collateral behind it. Credit cards and most personal loans fall into this category. When an unsecured borrower stops paying, the lender’s main recourse is to damage the credit record and, eventually, sue. In bankruptcy, unsecured creditors stand last in line and often recover little or nothing. That difference in risk is why unsecured loans carry higher interest rates.
Who Borrows: Consumer, Commercial, and Public Credit
Economists usually sort credit into three sectors based on who is doing the borrowing.
Consumer credit supports household spending. When you finance a car, carry a credit card balance, or take out a student loan, you’re borrowing against future income to cover a present need. Lenders evaluate your personal income, employment history, and credit score to decide how much to offer and at what rate. This is the sector most people interact with daily, and it’s the most heavily regulated at the federal level.
Commercial credit funds business operations. A manufacturer might borrow to build inventory before the holiday season; a startup might open a line of credit to cover payroll while waiting on receivables. Lenders look at the business’s revenue, cash flow, and assets rather than any individual’s personal finances. Terms reflect the specific industry’s risk profile.
Public credit involves governments borrowing to finance infrastructure, defense, social programs, or budget shortfalls. The U.S. Treasury issues bonds that investors buy, effectively lending money to the federal government. State and local governments do the same through municipal bonds. Repayment comes from future tax revenue. Because governments can raise taxes, their borrowing costs tend to be lower than those of private borrowers.
Revolving Credit Versus Installment Credit
Credit also differs in structure. Installment credit gives you a lump sum upfront, which you repay in fixed monthly payments over a set period. Mortgages, auto loans, and student loans all work this way. Once you pay off the balance, the account closes. If you need more money later, you apply for a new loan from scratch.
Revolving credit gives you a credit limit you can draw from repeatedly. Credit cards are the common example. You borrow what you need, pay it back in full or in part, and the available balance replenishes. The account stays open as long as you meet the minimum payment. The tradeoff for that flexibility is usually a higher interest rate, because the lender can’t predict how much you’ll borrow or when.
Your mix of installment and revolving accounts actually feeds into your credit score, which is one reason financial advisors suggest maintaining both types in good standing.
Why Interest Exists and How It’s Priced
Interest is the cost of using someone else’s money. It exists for two reasons. First, money available today is worth more than the same amount in the future, because you could invest it or spend it now, and lenders need compensation for giving up that option. Second, there’s always a chance the borrower won’t pay back the loan, and the interest rate prices in that risk.
The federal funds rate, which is what banks charge each other for overnight loans, anchors most other rates in the economy. As of early 2026, the Federal Reserve has held this rate at 3.50%–3.75%. Banks then set their prime rate, currently 6.75%, as a baseline for consumer and business lending. The rate you actually pay stacks additional percentage points on top of prime based on your credit profile, the loan type, and the term. That’s how the average credit card APR ends up near 21% even though the prime rate is under 7%.
Federal law requires lenders to show the full cost of borrowing before you sign. The Truth in Lending Act defines the finance charge as the total of all interest and fees over the life of the loan and requires lenders to express that cost as an annual percentage rate.2Office of the Law Revision Counsel. 15 USC Chapter 41 Subchapter I – Consumer Credit Cost Disclosure The APR bundles the interest rate with origination fees, broker fees, and other charges into a single number. Two loans with the same stated interest rate can have very different total costs once fees are included, so compare APRs rather than headline rates.
How the Banking System Creates Credit
Credit doesn’t just move existing money around. The banking system actually creates new purchasing power through lending. When a bank receives a $10,000 deposit, it doesn’t lock all of that money in a vault. It lends most of it out. The borrower spends that money, which lands in another bank account, and that bank lends most of it out again. This cycle, called the money multiplier, means the banking system as a whole produces several dollars of credit for every dollar of base deposits.
The main constraint on this process used to be reserve requirements, which forced banks to hold back a percentage of deposits. The Federal Reserve eliminated those requirements in March 2020 and has kept them at zero since.3Federal Reserve. Reserve Requirements Today, the practical limits on credit creation come from capital adequacy standards, which require banks to maintain a minimum ratio of capital to risk-weighted assets, and from the banks’ own willingness to take risk.
Most credit never flows directly from saver to borrower. Financial intermediaries sit in between. Commercial banks, credit unions, and similar institutions collect deposits from millions of individual savers and pool them into large reserves, then allocate those funds to borrowers who pass their underwriting standards. Without that pooling, a person wanting to borrow $300,000 for a house would need to find dozens of individual savers, negotiate with each one, and coordinate repayment to all of them. Banks absorb that friction. They profit from the spread between what they pay depositors and what they charge borrowers, which is also why the health of the banking system matters so much to the wider economy.
Credit cycles are the result of this system expanding and contracting over time. During economic booms, lenders loosen standards and credit flows freely, fueling more spending and investment. When conditions deteriorate, lenders tighten up, loans become harder to get, and the total volume of credit shrinks. The 2008 financial crisis was the most dramatic modern example: credit markets froze almost overnight, and the ripple effects took years to work through. These swings are why central banks spend so much effort trying to smooth the cycle through interest rate policy.
Credit Scores and What They Determine
At the consumer level, your credit score is the single most important number in determining what credit you can access and what it will cost. FICO scores, used in roughly 90% of U.S. lending decisions, range from 300 to 850 and are calculated from five categories in your credit report. Payment history carries the most weight at 35%, followed by amounts owed at 30%, length of credit history at 15%, new credit applications at 10%, and the mix of account types at 10%.
The practical impact is significant. A borrower with a 760 score might qualify for a mortgage at a rate close to prime, while a borrower with a 620 score could pay two or more percentage points higher on the same loan, adding tens of thousands of dollars over a 30-year term. Credit card issuers, auto lenders, landlords, and some employers all use these scores to make decisions, which makes the score itself a kind of condensed summary of everything a modern credit system is trying to measure: the probability that a specific borrower will keep the promise at the heart of every credit transaction.