Figures.Finance

Compound Interest Calculator

See how your money grows over time with the power of compounding. Add regular contributions to supercharge your results.

Final Balance
$144,573
Total Contributions
$58,000
Interest Earned
$86,573

Growth Over Time

Year-by-Year Breakdown

YearBalanceContributionsInterest
Yr 1$13,201$12,400$801
Yr 2$16,634$14,800$1,834
Yr 3$20,315$17,200$3,115
Yr 4$24,262$19,600$4,662
Yr 5$28,495$22,000$6,495
Yr 6$33,033$24,400$8,633
Yr 7$37,900$26,800$11,100
Yr 8$43,118$29,200$13,918
Yr 9$48,714$31,600$17,114
Yr 10$54,714$34,000$20,714
Yr 11$61,147$36,400$24,747
Yr 12$68,046$38,800$29,246
Yr 13$75,444$41,200$34,244
Yr 14$83,376$43,600$39,776
Yr 15$91,882$46,000$45,882
Yr 16$101,003$48,400$52,603
Yr 17$110,783$50,800$59,983
Yr 18$121,270$53,200$68,070
Yr 19$132,515$55,600$76,915
Yr 20$144,573$58,000$86,573

Understanding Compound Interest

Compound interest is one of the most powerful forces in personal finance. Unlike simple interest — which is only calculated on the original principal — compound interest is calculated on both the principal and the interest already earned. This means your balance grows faster and faster as time passes, a phenomenon often called the "snowball effect."

The key variables that determine your final balance are: your initial deposit (principal), the annual interest rate, how frequently the interest compounds (daily, monthly, or annually), whether you make regular contributions, and most importantly — how long you leave the money to grow. Time is the most powerful ingredient in compound growth.

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Consider two investors: one starts at age 25 and invests $5,000 per year for 10 years, then stops. The other waits until age 35 and invests $5,000 per year for 30 years. Assuming a 7% annual return, the early starter ends up with more money at retirement — despite contributing far less total capital. This illustrates why starting early matters enormously.

Use this calculator to model your savings goals, compare contribution strategies, or see how changing your interest rate assumption affects long-term outcomes. Whether you are planning for retirement, a home deposit, or an emergency fund, understanding compound growth helps you make smarter financial decisions today.

Frequently Asked Questions

What is compound interest?

Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, compounding causes your balance to grow exponentially over time.

How often should interest compound for the best returns?

The more frequently interest compounds, the more you earn. Daily compounding yields slightly more than monthly, which yields more than annually. However, the difference between daily and monthly compounding is usually small in practice.

What is the Rule of 72?

The Rule of 72 is a quick way to estimate how long it takes to double your money. Divide 72 by the annual interest rate: at 6% per year, your money doubles in roughly 12 years.

How do regular contributions affect compound growth?

Regular contributions dramatically accelerate wealth building. Each contribution immediately starts earning compound interest, so adding money consistently — even small amounts — has a large impact on your final balance thanks to the time value of money.

Is compound interest good for savings but bad for debt?

Exactly. When you save or invest, compound interest works in your favour, growing your wealth faster. When you carry debt (like a credit card), compound interest works against you, making the debt more expensive the longer it goes unpaid.

What return rate should I use for long-term investments?

For long-term stock market investments, many financial planners use 7–8% annually (the historical average real return of the S&P 500 after inflation). Conservative estimates use 4–5%. Always stress-test your plans with a lower rate.

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