Savings Account Interest Calculator
See exactly how your savings grow with compound interest — month by month, year by year.
| Year | Balance | Principal | Contributions | Interest Earned | Annual Interest |
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How to Use This Savings Account Interest Calculator
Enter your initial deposit, any monthly contributions you plan to add, your account's APY (Annual Percentage Yield), and how many years you'll save. Choose your compounding frequency (most savings accounts compound daily or monthly) and click Calculate Growth. The tool instantly shows your final balance, total interest earned, and a year-by-year breakdown table.
Why This Matters
Compound interest is often called the eighth wonder of the world — and for good reason. A 25-year-old who puts $5,000 into a high-yield savings account at 4.5% APY and adds just $200/month will have over $85,000 in 15 years, of which more than $25,000 is pure interest earned — money that required zero additional effort.
This matters most when comparing banks. The difference between a traditional savings account at 0.5% APY and a high-yield account at 4.5% APY on a $20,000 balance over 5 years is roughly $4,400 in extra interest. That's a vacation, a car payment, or a down payment contribution — all from simply choosing the right account.
People who benefit most from this tool include: first-time savers building an emergency fund, parents saving for college tuition, anyone comparing HYSAs (High-Yield Savings Accounts), and retirees living off interest income. Knowing your projected balance also helps you stay motivated — seeing your money grow on paper makes the habit stick.
How It's Calculated
The calculator uses the compound interest with regular contributions formula:
A = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) − 1) / (r/n)]
Where: A = final balance, P = initial principal, r = annual interest rate (decimal), n = compounding periods per year, t = time in years, PMT = monthly contribution converted to per-period amount. The APY slider reflects the stated annual rate, and the compounding frequency determines how often interest is credited to your balance.
Tips & Common Mistakes
- Use APY, not APR: Most savings accounts advertise APY (which already accounts for compounding). Don't confuse it with APR — APY will give you accurate results here.
- Don't ignore small rates: The difference between 4.0% and 4.5% sounds tiny, but on $50,000 over 10 years it's over $3,000 in extra earnings.
- Start early, not big: A 22-year-old saving $100/month beats a 30-year-old saving $300/month in total wealth by retirement — time beats amount.
- Check FDIC insurance: High-yield savings accounts at online banks are FDIC-insured up to $250,000 — they're just as safe as traditional banks.
- Interest rates change: This calculator assumes a fixed rate. Real account rates fluctuate, so treat the output as a projection, not a guarantee.
Frequently Asked Questions
What's the difference between APY and APR?
APY (Annual Percentage Yield) reflects the real return including compound interest, while APR (Annual Percentage Rate) is the base rate before compounding. For savings accounts, always use APY — it's what you'll actually earn. If your bank gives you an APR, you can convert it using: APY = (1 + APR/n)^n − 1.
How often should I compound for best results?
Daily compounding earns slightly more than monthly, which earns more than annually. However, for typical savings rates (under 6%), the difference between daily and monthly compounding is less than 0.01% — effectively negligible. Most online savings accounts compound daily, which is ideal.
Does this account for taxes on interest?
No — this calculator shows gross interest before taxes. In the US, savings account interest is taxed as ordinary income. If you're in the 22% federal tax bracket, multiply your interest earned by 0.78 to estimate after-tax returns. Tax-advantaged accounts like Roth IRAs have different rules.
What's a good APY for a savings account right now?
As of 2024, many high-yield savings accounts (HYSAs) at online banks offer 4.5–5.0% APY, while traditional brick-and-mortar banks typically offer 0.01–0.5%. Shopping around and moving your savings to an HYSA is one of the simplest ways to meaningfully increase your interest income.