Compound Interest
How compound interest works, compounding frequency, APY vs APR, and how to make your money grow faster over time.
What Is Continuous Compounding? The Math, the Formula, and What It Means in Practice
Continuous compounding is the theoretical limit of how often interest can compound. Here's what the formula means, how it compares to daily and monthly compounding, and where it actually shows up in finance.
Read ArticleCompound Interest: 401(k) vs. Taxable Account -- How Tax Treatment Changes Everything
The same 7% annual return produces very different outcomes in a 401(k), a Roth IRA, and a taxable brokerage account. Understanding why -- and which account to fill first -- is one of the highest-leverage financial decisions you can make.
Read ArticleThe Power of Starting Early: How 10 Years Can Be Worth More Than 30 Years of Saving
Starting to invest at 22 instead of 32 can be worth more than investing for 30 additional years later. The math behind compound interest is counterintuitive and more powerful than most people realize.
Read ArticleCompound Interest Calculator: A Complete Walkthrough With Real Scenarios
The compound interest calculator is the most versatile tool in personal finance. Here's a complete walkthrough — every input explained, five real scenarios modeled, and how to use it to answer any savings or investment question.
Read ArticleWhat Is Compound Interest Frequency? Daily vs. Monthly vs. Annual Compounding
Compounding frequency determines how often interest is calculated and added to your balance. Here's exactly how daily, monthly, and annual compounding differ — and when the difference actually matters.
Read ArticleThe Rule of 72 Explained: How to Estimate When Your Money Will Double
The Rule of 72 is the most useful mental math shortcut in personal finance. Divide 72 by the annual rate to estimate doubling time — no calculator needed. Here's how it works, when to use it, and how to apply it to savings, debt, and inflation.
Read ArticleSimple Interest vs. Compound Interest: What's the Real Difference?
Simple interest and compound interest sound similar but produce dramatically different results over time. Here's exactly how they differ, when each applies, and what the gap looks like with real numbers.
Read ArticleWhat Is Compound Interest and Why It's the Most Important Concept in Personal Finance
Compound interest is the single most powerful force in personal finance — for building wealth and for accumulating debt. Here's exactly how it works, with real numbers and a calculator to model your own situation.
Read ArticleSee compound interest in action.
Our free compound interest calculator shows year-by-year growth with any rate, compounding frequency, and monthly contribution.