Compound Interest Calculator
See how your investments grow over time with the power of compound interest. Add monthly contributions to accelerate your wealth building.
Investment Details
Growth Projection
Future Value
$54,713.58
Total Deposits
$34,000.00
Interest Earned
$20,713.58
Year-by-Year Growth
| Year | Deposits | Interest | Balance |
|---|---|---|---|
| Year 1 | $12,400.00 | $801.42 | $13,201.42 |
| Year 2 | $14,800.00 | $1,834.27 | $16,634.27 |
| Year 3 | $17,200.00 | $3,115.28 | $20,315.28 |
| Year 4 | $19,600.00 | $4,662.39 | $24,262.39 |
| Year 5 | $22,000.00 | $6,494.83 | $28,494.83 |
| Year 6 | $24,400.00 | $8,633.24 | $33,033.24 |
| Year 7 | $26,800.00 | $11,099.74 | $37,899.74 |
| Year 8 | $29,200.00 | $13,918.03 | $43,118.03 |
| Year 9 | $31,600.00 | $17,113.55 | $48,713.55 |
| Year 10 | $34,000.00 | $20,713.58 | $54,713.58 |
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How It Works
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. This "interest on interest" effect causes wealth to grow exponentially over time, which is why Albert Einstein reportedly called it the "eighth wonder of the world."
The formula is: A = P(1 + r/n)^(nt), where A is the future value, P is the principal, r is the annual interest rate, n is the number of times interest is compounded per year, and t is the number of years.
When you add regular monthly contributions, the growth accelerates significantly. Even small monthly additions can make a dramatic difference over long time periods. This is why financial advisors recommend starting to invest early — time is the most powerful factor in compound growth.
Worked example: $10,000 invested at 7% compounded annually grows to about $76,100 in 30 years — $66,100 of it earned interest, most of which accrues in the later years as the base grows. A shortcut for doubling time is the Rule of 72: at 7%, money doubles roughly every 72 ÷ 7 ≈ 10.3 years.
Frequently Asked Questions
Written by the Tools & Deals Hub Editorial Team · Reviewed by Durga Prasad Mogulothu, Founder · Last reviewed:
Sources & further reading
- CFPB — Consumer tools (loans, mortgages, savings)
- Investor.gov — Free financial calculators (U.S. SEC)
Results are estimates for planning, not professional advice. Figures can change after publication — check the source for current numbers.