Compound Interest Calculator
See how your savings or investments grow over time with compounding.
Initial deposit or investment
Expected yearly return
Number of years to grow
Extra added each month (end of period)
| Year | Ending Balance | Interest Earned (Year) |
|---|
Showing annual progress with compounding and monthly contributions (if any).
How Compound Interest Works
Compound interest is the interest you earn on both your original money (principal) and on the interest you previously earned. It’s often called “interest on interest” and it can make your savings grow faster over time. This calculator shows you exactly how much your money will grow based on a fixed annual rate, compounding frequency, and optional monthly additions.
If you invest $5,000 at 7% annual interest compounded monthly for 10 years with no extra deposits, the future value becomes about $10,062. That’s more than double your original amount because of compounding. Add $100 monthly and the final amount jumps to over $27,000. The magic is time and consistency.
📈 Real-Life Example: Retirement Savings
Starting with $10,000, adding $200 monthly, 8% return over 30 years = $348,000+ total. Compound interest did 70% of the work.
🏦 High-Yield Savings
$5,000 at 4.5% APY compounded daily yields $7,886 after 10 years without extra deposits.
💡 Tip box: The more frequent the compounding, the faster your money grows. Daily compounding beats monthly, but the difference shrinks at higher rates. For long-term investing, time in the market is more important than frequency.
Table of Truth: Compound Interest Examples
Check these common scenarios to verify your understanding.
| Principal | Rate | Years | Monthly Add | Future Value |
|---|---|---|---|---|
| $1,000 | 5% | 10 | $0 | $1,647.01 |
| $5,000 | 7% | 15 | $100 | $47,654.93 |
| $10,000 | 6% | 20 | $0 | $32,071.35 |
| $2,500 | 8% | 5 | $50 | $7,634.87 |
Common Mistakes People Make
Frequently Asked Questions (People Also Ask)
What is the formula for compound interest?
A = P (1 + r/n)^(nt) for lump sum. For monthly contributions, use the future value of a series formula. This calculator does both automatically.
Does compound interest work for loans?
Yes, compound interest on loans (credit cards, mortgages) works against you. Paying more than the minimum reduces the compounding effect. This tool helps you see investment growth, but you can invert thinking for debt.
What’s the difference between simple interest and compound interest?
Simple interest only earns on the principal. Compound interest earns on principal + accumulated interest. For long periods, compound interest yields dramatically higher returns.
How often should I compound my savings?
For most savings accounts, daily or monthly compounding is standard. Daily gives a tiny edge, but the biggest factor is the annual percentage yield (APY). Use our calculator to compare frequencies.
Can I use this calculator for retirement planning?
Absolutely. Enter your current savings as principal, expected annual return (e.g., 7-9% for stocks), monthly contribution, and number of years until retirement. The result shows your projected nest egg.
📌 Why SabiCalculator? No sign-up, no email, instant results. Built for humans who just want the numbers without financial jargon. Trusted by students, investors, and everyday savers.
© SabiCalculator — Compound Interest Tool. All calculations run locally in your browser. Past performance doesn’t guarantee future results. Use for estimation only.
