← Personal Finance: Money Skills That Actually Work
Lesson
Good debt vs bad debt and how interest compounds against you
Learner can distinguish high-interest 'bad' debt from lower-cost debt and explain how interest compounds against them.
How debt grows when you are not looking
Good debt, bad debt, and the compound trap
Not all debt is equal. Lower-cost debt — like a fixed-rate mortgage or a student loan — tends to fund something that holds or builds value, and the interest rate is relatively low. High-cost debt — credit cards, payday loans, buy-now-pay-later plans — typically carries a very high Annual Percentage Rate (APR) and funds spending that is already gone by the time the bill arrives. APR tells you how much you pay in interest per year, expressed as a percentage of the outstanding balance.
Here is the dangerous part: interest does not stay flat. Each month the lender calculates interest on whatever balance remains, so if you do not pay the balance in full, next month's interest is calculated on a larger number. This is compound interest working against you.
A real example shows just how brutal this can be. Take a $5,000 credit-card balance at 20% APR. If you pay a flat $100 every month — which feels like a reasonable amount — you will need about 109 months (roughly 9 years) to clear the debt, and you will have paid approximately $10,840 in total. That is more than twice the original $5,000 balance. The extra $5,840 is pure interest that went to the lender, not to anything you own or enjoy.
The core lesson: the higher the APR and the smaller your monthly payment relative to the balance, the more time interest has to compound — and the more you ultimately pay. Identifying which of your debts carries the highest APR is the first step to escaping the trap.
Lesson notes
Good debt, bad debt, and the compound trap
Not all debt is equal. Lower-cost debt — like a fixed-rate mortgage or a student loan — tends to fund something that holds or builds value, and the interest rate is relatively low. High-cost debt — credit cards, payday loans, buy-now-pay-later plans — typically carries a very high Annual Percentage Rate (APR) and funds spending that is already gone by the time the bill arrives. APR tells you how much you pay in interest per year, expressed as a percentage of the outstanding balance.
Here is the dangerous part: interest does not stay flat. Each month the lender calculates interest on whatever balance remains, so if you do not pay the balance in full, next month's interest is calculated on a larger number. This is compound interest working against you.
A real example shows just how brutal this can be. Take a $5,000 credit-card balance at 20% APR. If you pay a flat $100 every month — which feels like a reasonable amount — you will need about 109 months (roughly 9 years) to clear the debt, and you will have paid approximately $10,840 in total. That is more than twice the original $5,000 balance. The extra $5,840 is pure interest that went to the lender, not to anything you own or enjoy.
The core lesson: the higher the APR and the smaller your monthly payment relative to the balance, the more time interest has to compound — and the more you ultimately pay. Identifying which of your debts carries the highest APR is the first step to escaping the trap.