Compound Interest Calculator
Calculate compound interest with monthly contributions. See future value, interest earned, and yearly growth - free, instant, 100% private.
Future value
Balance growth
Total principal
Interest earned
Interest share of final balance
Year-by-year breakdown
| Year | Contributed | Interest | Balance |
|---|---|---|---|
| 1 | $11,200.00 | $539.50 | $11,739.50 |
| 2 | $12,400.00 | $1,168.01 | $13,568.01 |
| 3 | $13,600.00 | $1,890.06 | $15,490.06 |
| 4 | $14,800.00 | $2,710.44 | $17,510.44 |
| 5 | $16,000.00 | $3,634.20 | $19,634.20 |
| 6 | $17,200.00 | $4,666.60 | $21,866.60 |
| 7 | $18,400.00 | $5,813.23 | $24,213.23 |
| 8 | $19,600.00 | $7,079.91 | $26,679.91 |
| 9 | $20,800.00 | $8,472.79 | $29,272.79 |
| 10 | $22,000.00 | $9,998.32 | $31,998.32 |
Features
100% Browser-Based
Your financial inputs never leave your device. All math runs locally in your browser.
Free & No Sign Up
No registration, no limits, no hidden fees. Open the page and start calculating.
Instant Results
Every keystroke updates the future value, interest earned, and growth chart in real time.
Five Compounding Frequencies
Annual, semiannual, quarterly, monthly, or daily compounding - the math stays exact for each.
Monthly Contributions
Model regular deposits on top of your initial balance to see how saving accelerates growth.
Year-by-Year Breakdown
A full table of contributed principal, interest earned, and running balance for every year.
How to Calculate Compound Interest?
- Enter your initial deposit and optional monthly contribution.
- Type the annual interest rate and the number of years.
- Pick a compounding frequency - monthly and daily are the most common.
- Read your future value, interest earned, and interest share instantly.
- Scroll down for the year-by-year growth table.
When to Use the Compound Interest Calculator
Retirement Planning
Project how today's savings grow over decades and see whether you are on track for your target.
Savings Goal Check
Test whether your current deposit plus monthly contributions will reach a goal like a house down payment.
Comparing Investments
Run the same deposit across different rates and compounding frequencies to compare outcomes side by side.
Teaching the Snowball Effect
Show students or family how time and reinvested interest turn small deposits into large balances.
Tips for Using Compound Interest
- ✓ Time matters more than rate: doubling your years usually beats doubling your rate.
- ✓ Compare like with like - an 8% annual rate compounded monthly is effectively about 8.3% per year.
- ✓ Inflation erodes purchasing power: subtract it from your rate for a realistic real-return view.
- ✓ Contributions early in the schedule earn the most interest - starting now beats starting perfectly.
- ✓ Remember taxes: interest income is usually taxable, so post-tax returns will be lower than shown.