Knowing your net worth is important for financial planning, but for business owners, the math can get a little tricky.

Many savers spend years juggling calculators and advice, yet a single formula could reveal whether your nest egg is on track for the future.

Here’s how the Rule of 72 works: Divide 72 by your expected annual interest rate (as a percentage, not a decimal). The answer is roughly the number of years it will take for your money to double. For ...