What is money?

What money is for

What is money? We all use it every single day. And yet, only one in three adults in the world understands basic ideas like inflation or compound interest. How does money really work? In the next few minutes, you'll see where yours goes, you'll work out how much it grows when you put it to work, and you'll walk away with a plan to manage it better starting today.

By the way, this is my house in MindHaOS, and this room, Finance, is where I keep track of my expenses, my income and my savings goals. Let's get started.

Money is an agreement: a bill or a number on a screen is worth something because we all agree that it is. It lets us trade, measure what things are worth, and store value for the future.

But that last job has an enemy: inflation. If prices go up three percent a year, they double in about twenty-four years, and the money you kept under your mattress buys half as much.

And earning more isn't enough. In Florida, researchers followed lottery winners: five years later, the big winners were going bankrupt almost as often as the small ones. The prize only delayed the problem.

Managing your money well doesn't depend on how much you earn, but on a simple subtraction: what comes in, minus what goes out, is what you have left to build with. This guide is here so that subtraction works in your favor.

A brief history of money

Almost four thousand years ago, the Code of Hammurabi, in Babylon, was already capping interest: at most, twenty percent a year on loans of silver and a third on loans of barley. Debt is almost as old as writing.

Around the year six hundred before the common era, in the kingdom of Lydia, in what is now Turkey, the first coins appeared: pieces of electrum, a natural mix of gold and silver, with a stamp that guaranteed their weight.

In 1024, in Song dynasty China, the government began issuing the jiaozi, the world's first official paper money: people there used iron coins, and carrying them around to trade was impossible.

In 1920, in Boston, Charles Ponzi promised a fifty percent return in forty-five days. He paid the first investors with the money from the new ones, until the whole thing collapsed. His name stuck to that kind of fraud forever.

And in 1971, President Richard Nixon cut the last link between the dollar and gold. Since then, almost all the world's money is worth something because we trust whoever issues it, not because of metal kept in a vault.

Where your money goes

The first step is knowing where it goes. For one month, write down everything you spend, down to the coffee on the corner. Almost everyone finds expenses they didn't know they had.

Those small expenses, the little everyday leaks, add up faster than you think. Try it here: pick something you buy every day and see how much it takes in a year, and in ten.

A simple way to split what you earn is the fifty, thirty, twenty rule, made popular by Elizabeth Warren: half for your needs, thirty percent for your wants and twenty for saving or paying off debt. Type in your income here and see how it works out.

And the trick that works best is paying yourself first: setting your savings aside on payday, not whatever is left at the end of the month. In the Save More Tomorrow program, by Richard Thaler and Shlomo Benartzi, workers went from saving three and a half percent of their pay to almost fourteen percent.

Your cushion and your debts

Before you invest, build a cushion. In the United States, only sixty-three percent of adults could cover an unexpected four-hundred-dollar expense with cash or savings. An emergency fund keeps you out of debt when something breaks or you lose your job.

The usual advice is to put together three to six months of your basic expenses, little by little, somewhere safe you can get to quickly. Work out here how much yours would be and how long it would take you to build it.

I build mine in my Finance room in MindHaOS: on payday I set my savings aside, and from the piggy bank on my desk I can see how far along I am with each goal.

Credit card debt is among the most expensive kinds: in the United States, the average interest rate went above twenty percent a year in 2024. Whatever you buy in installments with interest can end up costing you much more.

And paying only the minimum is the most expensive trap of all. Try it here: enter a debt, its interest rate and what you pay each month, and see how many months it takes you to get out and how much you pay in interest.

To get out of several debts, there are two methods: the avalanche, which pays off the highest-interest one first and saves you more, and the snowball, which pays off the smallest one first. A 2012 study found that clearing accounts completely, one by one, helps people not give up.

Put your money to work

Compound interest means earning interest on your interest: at first you barely notice it, and then the curve shoots up. Try it here: choose how much you set aside each month, at what rate and for how many years, and see how much you put in and how much the interest put in.

A shortcut for doing the math in your head is the rule of seventy-two: divide seventy-two by the annual rate and you'll know how many years it takes your money to double. At six percent, about twelve years.

That's why time is worth more than the amount. If two people set aside the same amount each month at six percent a year, one from age twenty-five and the other from thirty-five, by sixty-five the first will have almost twice as much, even though she only put in a third more.

Investing always carries risk: what can earn more can also fall further. Three principles help: think long term, with only money you won't need soon; don't put all your eggs in one basket; and don't put your money into something you don't understand.

And watch out for fees, because they compound too: if your money earns seven percent a year and you pay one percent in fees, after thirty years you end up with about a quarter less.

And be wary of anyone who promises you high, guaranteed returns: they don't exist. If it sounds too good to be true, it's almost always a fraud, just like Ponzi's.

Your plan to get started

Give what you want a name and a date: “save more” isn't the same as “put together the down payment on a car in eighteen months.” With the amount and the date, you know how much to set aside each month.

Automate everything you can: savings that go out on their own on payday, and fixed bills on automatic payment. The decisions you don't have to make every month are the ones that actually get done.

And once a month, check how much came in, how much went out and how far you've come. Ten minutes is enough to correct course before a bad month turns into a bad year.

Remember that this guide is for information only and is not financial or investment advice: it doesn't tell you what to invest in. Before taking out a loan or making an investment, compare, read the terms and, if you need to, talk to a registered advisor.

To sum up: write down where your money goes, pay yourself first, build your cushion, get out of expensive debt, and let time and compound interest work for you.

If you want to put it into practice the way I do, Finance, the money room in MindHaOS, keeps your money flow, with expenses, income and balance; your savings goals and debt goals, with calculators; and your net worth, so you can watch it grow. The link is in the description, along with this interactive guide. See you in the next one.