Uploaded March 2026 | Updated September 2026, 2 weeks ago
How long does it take for your money to double?
This is called the Rule of 72.
If you’re getting 8% interest then divide 72 by 8 and you get 9 year. This means 9 years to double your money, this is the rule of 72.
Divide interest rate by 72
The Rule of 72 is a simple mental shortcut used to estimate how long it will take for an investment to double in value based on a fixed annual interest rate. To use it, you divide 72 by the interest rate.
For example, if your money is earning 8% per year, you do 72 ÷ 8 = 9, meaning your investment will roughly double in about 9 years. It works best with interest rates between about 6% and 10% and assumes compound interest is at play.
This rule is powerful because it lets you quickly compare investment opportunities without needing a calculator.
For instance, if one investment earns 6% and another earns 12%, the Rule of 72 shows that money doubles in 12 years at 6% but only 6 years at 12%—a dramatic difference over time. While it’s an approximation (not exact), it’s accurate enough for fast decision-making and is widely used in finance to illustrate the impact of compounding.
#Mathisfun #streetinterview #financialfreedom
How long does it take for your money to double?
This is called the Rule of 72.
If you’re getting 8% interest then divide 72 by 8 and you get 9 year. This means 9 years to double your money, this is the rule of 72.
Divide interest rate by 72
The Rule of 72 is a simple mental shortcut used to estimate how long it will take for an investment to double in value based on a fixed annual interest rate. To use it, you divide 72 by the interest rate.
For example, if your money is earning 8% per year, you do 72 ÷ 8 = 9, meaning your investment will roughly double in about 9 years. It works best with interest rates between about 6% and 10% and assumes compound interest is at play.
This rule is powerful because it lets you quickly compare investment opportunities without needing a calculator.
For instance, if one investment earns 6% and another earns 12%, the Rule of 72 shows that money doubles in 12 years at 6% but only 6 years at 12%—a dramatic difference over time. While it’s an approximation (not exact), it’s accurate enough for fast decision-making and is widely used in finance to illustrate the impact of compounding.
#Mathisfun #streetinterview #financialfreedom
