How Money Actually Works: Banks, Central Banks, and Where Money Comes From

Ask most people where money comes from and they will describe a printing press: the government runs the press, money rolls off it, and that money flows into the economy. It is a tidy story. It is also wrong about roughly 90% of the money you use.

The Bank of England stated it plainly in its landmark 2014 paper, Money Creation in the Modern Economy: “The majority of money in the modern economy is created by commercial banks making loans.” Physical notes and coins — the part an actual press produces — are a rounding error in the total money supply. The rest is digital, and it is conjured into existence by ordinary banks every time someone takes out a mortgage, a car loan, or a business credit line.

Understanding that one fact reorganizes everything else: inflation, interest rates, debt, recessions, and why central banks behave the way they do. This is the foundational mechanism. Let us take it apart, in order — cause, mechanism, consequence.

Cause: money is a claim, not a commodity

Money has not been a physical thing you could redeem for gold since 1971, when President Nixon ended the dollar’s convertibility into gold and broke the Bretton Woods system (see the Federal Reserve History account of that decision). Since then, every major currency has been fiat money: it has value because a government declares it legal tender, because you can pay your taxes with it, and because everyone else accepts it.

The European Central Bank describes modern money as having three jobs: it is a medium of exchange, a unit of account, and a store of value. Critically, most of what does those three jobs is not cash at all. It is a number in a database — a deposit, which is simply a promise from your bank that you can withdraw that amount on demand.

That distinction is the cause of everything that follows. A deposit is a bank’s liability — a debt the bank owes you. And here is the part that surprises people: a bank can create that liability out of nothing.

Mechanism: how a bank creates money out of a loan

Picture the textbook story you were probably taught. A saver deposits $1,000. The bank keeps $100 in reserve and lends $900 to a borrower. That borrower’s spending lands in another bank, which lends $810, and so on — the “money multiplier.” It is intuitive, and the Bank of England says it is “not an accurate description” of how banks actually work.

The reality runs in the opposite direction. A bank does not lend out money it already has. It creates new money by writing two numbers at once.

When a bank approves your $300,000 mortgage, it does not move $300,000 from a vault into your account. It types $300,000 into your account as a deposit (a new liability) and simultaneously records a $300,000 loan as an asset. Both sides of the balance sheet expand by $300,000. The money in your account is brand-new money that did not exist seconds earlier. This is the heart of how banks make money — and of how money is created.

The mirror image matters just as much. When you repay the loan, that money is destroyed. The deposit shrinks, the loan asset shrinks, and the money supply contracts. New lending inflates the money supply; repayment deflates it.

So what stops banks from creating infinite money? Three real constraints, in order of how much they bite:

1. Profitability and demand. A bank only creates money when it can make a profitable loan to a creditworthy borrower who wants one. No demand, no creation.
2. Capital requirements. Banks must hold capital (their own funds) against their loans to absorb losses. This, not a reserve ratio, is the binding modern limit.
3. The central bank’s interest rate. By setting the price of reserves, the central bank makes lending more or less attractive across the whole system.

Notice what is missing from that list: a fixed reserve ratio. The US Federal Reserve set the reserve requirement to zero in March 2020 and has not restored it. The “fractional reserve” name survives the system it described.

Mechanism, part two: what the central bank actually controls

If commercial banks create most of the money, what is the central bank for? It governs the price and availability of the raw material banks build on — reserves — and it sets the interest rate that ripples through every loan in the economy.

Here is the layered structure, from the central bank outward:

Layer	Who creates it	What it is	Roughly how big
Physical cash	Central bank	Notes and coins	A small fraction of money
Central bank reserves	Central bank	Banks’ accounts at the central bank	Used between banks, not by you
Commercial bank deposits	Commercial banks	The money in your account	The overwhelming majority

Source: Bank of England, Money Creation in the Modern Economy (2014); Federal Reserve, Reserve Requirements.

The central bank’s main lever is the policy interest rate. In the US, the Federal Reserve targets the federal funds rate and steers it using open market operations — buying and selling government bonds to add or drain reserves. Raise the rate and borrowing gets more expensive, lending slows, and money creation cools. Cut the rate and the reverse happens. That single dial is how a central bank tries to manage inflation and employment, the subject of how interest rates are set.

In a crisis, the central bank wears a second hat: lender of last resort. When banks stop trusting each other and the system seizes, the central bank lends freely against good collateral to stop a liquidity panic from becoming a solvency collapse. This is also where quantitative easing lives — the central bank creating new reserves to buy bonds at scale, pushing down longer-term rates when the policy rate is already near zero, the subject of what QE really is.

Consequence: an economy that runs on debt and confidence

Once you see that money is created by lending, three consequences follow that explain headlines you read every week.

First, the money supply is elastic and credit-driven. Booms are periods of rapid money creation as lending surges; recessions often involve money destruction as lending contracts and loans are repaid or written off. The growth of money and the growth of debt are nearly the same phenomenon viewed from two sides of the balance sheet. This is why a credit crunch can shrink the economy even when no physical cash has been burned.

Second, the system depends entirely on confidence. A bank deposit is a promise to pay on demand, but no bank holds enough cash to honor all promises at once. If depositors lose faith and demand their money simultaneously, an otherwise sound bank can fail — a bank run. This is the structural reason deposit insurance and central-bank backstops exist: they are confidence machinery, not vaults of gold. When that confidence breaks at the level of an entire currency, you get how currency collapse happens.

Third, who gets the new money matters. Because new money enters the economy through loans, it flows first to those banks judge creditworthy — and asset-owners and large borrowers tend to be first in line. The same mechanism that makes the system flexible also shapes who benefits when money is cheap, a thread that runs straight into how the rich stay rich and why everything keeps getting more expensive.

If you want to feel the long-run power of this credit-and-interest machine on your own balance sheet rather than the system’s, the compound interest calculator is the most direct demonstration: the same arithmetic that lets banks expand the money supply also governs what a loan costs you over decades.

The machine in one paragraph

Cause: money is a fiat claim, a promise rather than a commodity. Mechanism: commercial banks create most of it by issuing loans, expanding both sides of their balance sheet at once, constrained by capital and demand rather than a reserve of cash — while the central bank sets the interest rate and supplies reserves, acting as lender of last resort and, when needed, buying bonds with newly created reserves. Consequence: an economy whose money supply rises and falls with debt, runs on confidence, and channels new money first to borrowers and asset-holders. Every other money story — inflation, rates, debt, wealth — is a branch of this one.

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This article explains how the monetary system works. It is educational and is not financial, tax, or legal advice. Figures are dated and, where noted, rounded or directional. Consult a qualified professional for your own situation.