Compound Interest Calculator
Calculate how your investment grows with compound interest over time.
✓ See the power of compound interest. Watch your money grow exponentially as interest earns interest over time.
Calculator
Your Results
The Magic of Compound Interest
Albert Einstein allegedly called compound interest "the eighth wonder of the world." It's the process where your investment earnings generate their own earnings. Start with $10,000 at 7% annual return: you earn $700 in year one. In year two, you earn 7% on $10,700—not just your initial $10,000. This accelerating growth is compound interest.
Compounding Frequency Matters
Daily: Interest is calculated and added daily (365 times per year). Best for savings accounts.
Monthly: Interest compounds 12 times per year. Common for CDs and some accounts.
Quarterly: 4 times per year. Typical for bonds.
Annually: Once per year. Common for investment returns.
More frequent compounding means higher returns. The difference between daily and annual compounding at 7% over 20 years is thousands of dollars on a $10,000 investment.
Time is Your Greatest Asset
Starting early is crucial. A $5,000 investment at age 25 earning 7% annually becomes $96,000 by age 65 (40 years). The same $5,000 invested at age 35 becomes only $36,000 by age 65 (30 years). That 10 years of difference more than doubles your outcome.
Boost Your Compound Returns
- Start Early: Time amplifies compound interest exponentially.
- Invest Regularly: Add money consistently to benefit from compounding on larger amounts.
- Reinvest Earnings: Don't withdraw interest. Let it compound.
- Seek Higher Returns: A 1-2% difference in annual return compounds to huge differences over decades.
- Keep Costs Low: High fees on investments reduce your compounding base.
Related Calculators
FIRE Calculator
Calculate when you can reach financial independence.
Learn more →US Income Tax Calculator
Estimate your federal income tax (single filer, simplified).
Learn more →Break Even Calculator
Calculate break even point.
Learn more →Profit Margin Calculator
Calculate profit margin percentage instantly.
Learn more →Additional Resources
Trusted Sources
- SEC Investment Growth ↗
Understanding compound interest in investing
- Federal Reserve Economic Data ↗
Economic data and interest rate information
- Investopedia Compound Interest ↗
Detailed compound interest explanation
About This Calculator
This calculator uses industry-standard formulas and financial methodologies. Always consult with a qualified financial advisor before making investment decisions.
Frequently Asked Questions
Get answers to common questions about this calculator
Q: What's the Rule of 72?▼
A: The Rule of 72 is a quick way to estimate doubling time. Divide 72 by your annual interest rate. At 7% returns, your money doubles every ~10 years (72/7). At 10%, every ~7 years (72/10). This rule is accurate for rates between 5-8%.
Q: How does regular investing amplify compound interest?▼
A: Adding money regularly (dollar-cost averaging) increases your compounding base. $100/month invested for 30 years at 7% becomes ~$130,000, even though you only contributed $36,000. The extra $94,000 is pure compounding power.
Q: What rate of return should I expect?▼
A: S&P 500 historical average is ~10% annually, but this varies wildly year-to-year. Long-term: expect 7-10% for stock-heavy portfolios, 3-5% for balanced portfolios, 2-3% for bond-focused portfolios. Past performance doesn't guarantee future results.
Q: How does inflation affect compound interest?▼
A: Inflation erodes purchasing power. A 7% return in a 2% inflation environment is really a 5% real return. Always consider inflation when planning investments. Treasury inflation-protected securities (TIPS) provide inflation-adjusted returns.