Simple interest is calculated only on your original principal — if you deposit $10,000 at 5%, you earn $500 every year regardless of balance. Compound interest is calculated on your growing balance — you earn interest on your interest. Over long periods, compounding creates exponential growth. For serious wealth building, compound interest is the superior instrument.

APY (Annual Percentage Yield) is the effective annual return when compounding is taken into account. A savings account advertised at 5% APR compounding monthly actually produces an APY of 5.116%. When comparing savings products, always compare APY (not APR) for an apples-to-apples comparison. This calculator shows you the effective APY in the results panel.

More frequent compounding means your interest starts earning its own interest sooner. Daily compounding produces marginally more than monthly, which beats quarterly, which beats annual. At 5% for 10 years: daily compounding produces about $16,487 vs. $16,289 for annual compounding on a $10,000 deposit. When choosing a savings account, look for the highest APY with the most frequent compounding period.

For short-term goals and emergency funds, a high-yield savings account is ideal. But for long-term wealth building (10+ years), savings account rates have historically underperformed inflation. Most advisors recommend keeping 3–6 months of expenses in savings and investing the rest in higher-yield instruments. Our guide on wealth management strategies covers how to allocate capital across asset classes.

As of 2026, competitive high-yield savings accounts and money market accounts offer between 4.5%–5.5% APY in the US. Traditional bank savings accounts often pay well under 1%. Online banks and credit unions typically offer the most competitive rates. See our overview of the best investments for 2026 for current opportunities across all asset classes.

First, establish a 3–6 month emergency fund in a liquid savings account. Then eliminate high-interest debt (anything above ~7%). After that, every additional dollar above your emergency fund is better deployed in investments than in savings. Our guide on how much to save for retirement covers target benchmarks by age and income level.