Financial Calculators
The ultimate suite of tools for your financial journey.
Core Personal Finance
Debt & Credit
Real Estate
Investing
Tax & Cash Flow
Advanced / FIRE
Growth Settings
Power of Compounding
Compound interest is the interest on your interest. In the example above, precise and consistent monthly contributions of $500 grow exponentially.
Tip: Time is your best friend. Start early!
Financial Calculator Guide
The Rule of 72
A quick way to estimate how long it takes to double your money. Divide 72 by your annual interest rate. For example, at 7% return, money doubles in roughly 10 years (72 / 7 ≈ 10.2).
Start Early
The most powerful variable in compound interest is time. Starting 10 years earlier can mean hundreds of thousands more at retirement, even with smaller contributions.
Consistency Beats Timing
Regular monthly contributions (Dollar Cost Averaging) smooth out market volatility and remove the stress of trying to time the market perfectly.
Tax-Advantaged Growth
Use 401(k)s and IRAs to let your money compound tax-free or tax-deferred. A 7% return in a taxable account is effectively ~5% after taxes for high earners.
Financial Calculator Guide
The Rule of 72
A quick way to estimate how long it takes to double your money. Divide 72 by your annual interest rate. For example, at 7% return, money doubles in roughly 10 years (72 / 7 ≈ 10.2).
Inflation Impact
Remember that $1 million in 30 years won't buy as much as it does today. Historically, inflation averages about 3%. To maintain purchasing power, aim for returns above this benchmark.