Personal finance basics

Personal finance is the management of your own money: earning, spending, saving, borrowing and protecting against risk. The details, such as tax rules and accounts, differ between countries, but the underlying principles are much the same everywhere.

This guide explains those principles for general education. It is not financial advice, and anyone facing a major decision should consider speaking to a qualified, independent adviser.

A budget is simply a plan for your money. It starts by tracking income and spending for a few weeks or months to see where money actually goes, which often reveals surprises.

One popular rule of thumb, the 50/30/20 approach, suggests roughly 50 percent of after-tax income for needs, 30 percent for wants and 20 percent for saving and paying off debt. The exact split matters less than the habit of deciding in advance where money goes rather than finding out at the end of the month.

Interest is the price of money over time. When you save, a bank or investment pays you interest; when you borrow, you pay it. Compound interest means interest is earned on previous interest, so growth accelerates over long periods.

A useful approximation is the rule of 72: divide 72 by the annual interest rate to estimate how many years it takes money to double. At 6 percent a year, money doubles in about 12 years. The same arithmetic works against borrowers: debts at high interest rates grow quickly if left unpaid.

• Not all debt is equal: borrowing for a home or education may build long-term value, while high-interest consumer debt usually does not.
• Credit cards and payday loans can carry very high interest rates.
• The annual percentage rate, or APR, shows the yearly cost of borrowing including many fees.
• Paying more than the minimum on a debt greatly reduces total interest paid.
• A common strategy is to pay off the highest-interest debts first.

An emergency fund, money set aside for unexpected events like job loss or a broken boiler, prevents people from falling into debt when something goes wrong. Many guides suggest aiming for several months of essential expenses, built up gradually.

Automating savings, so a set amount moves to a savings account on payday, makes saving more reliable, because it relies on a default rather than a monthly decision.

Inflation slowly reduces what money can buy, so cash kept for decades loses value. Investing aims to grow money faster than inflation, but it involves risk: the value of shares and many other investments can fall as well as rise.

Widely accepted principles include diversification, spreading money across many investments so no single failure is disastrous; keeping costs low, since fees compound too; investing for the long term rather than trying to time the market; and being very wary of anything promising high returns with little risk, which is a classic sign of fraud.