How Compound Interest Grows Your Savings
Compound interest means you earn interest on your interest. The difference between simple and compound interest grows dramatically over time — especially with regular monthly deposits.
| Starting Balance | APY | Monthly Add | After 10 Years | Interest Earned |
|---|---|---|---|---|
| $10,000 | 4.5% | $200 | ~$45,900 | ~$11,900 |
| $5,000 | 5.0% | $500 | ~$82,000 | ~$17,000 |
| $25,000 | 4.0% | $0 | ~$37,000 | ~$12,000 |
Frequently Asked Questions
Compound interest earns interest on both the principal and previously earned interest. For example, $10,000 at 5% compounded monthly grows to $10,511.62 after 1 year — more than the $10,500 you'd earn with simple interest. The more frequently interest compounds, the more you earn.
APR (Annual Percentage Rate) is the stated interest rate. APY (Annual Percentage Yield) accounts for compounding frequency and shows the true annual return. A 5% APR compounded monthly equals a 5.116% APY. Banks are required to disclose APY, making it easier to compare accounts.
Financial experts recommend 3–6 months of living expenses in an emergency fund (liquid savings). Beyond that, high-yield savings accounts, CDs, or money market accounts are good for short-term goals (1–5 years). For long-term goals, consider investing in index funds.
A high-yield savings account (HYSA) offers significantly higher interest rates than traditional savings accounts — often 4–5% APY vs 0.01–0.5% at brick-and-mortar banks. HYSAs are typically offered by online banks and are FDIC-insured up to $250,000.
Most savings accounts compound interest daily or monthly. Daily compounding earns slightly more than monthly. A $10,000 deposit at 5% APR compounded daily earns $512.67/year vs $511.62/month compounding — a small but real difference that grows over time.
Yes — interest earned on savings accounts is taxable as ordinary income in the U.S. You'll receive a 1099-INT form from your bank if you earn more than $10 in interest. The tax rate depends on your income bracket (10%–37%). Municipal bonds offer tax-exempt interest as an alternative.