Compound Interest Calculator
Calculate compound interest and investment growth over time. See how your savings grow with regular contributions and compound interest.
Calculate Your Investment Growth
What is Compound Interest?
Compound interest is the interest calculated on the initial principal and the accumulated interest from previous periods. It's often called "interest on interest" and can significantly boost your investment returns over time.
Example Calculation
With a $10,000 initial investment, 7% annual return, and $500 monthly contributions over 10 years:
- • Total invested: $70,000.00
- • Interest earned: $36,639.02
- • Final value: $106,639.02
Key Principles
- • Interest is earned on both principal and prior interest
- • More frequent compounding increases returns
- • Time allows compound growth to accelerate
- • Regular contributions amplify the effect
The Compound Interest Formula
A = P(1 + r/n)nt
- A = Final amount (principal + interest)
- P = Principal (initial investment)
- r = Annual interest rate (as decimal)
- n = Compounding frequency per year
- t = Time in years
This calculator uses this standard formula to compute your projected investment growth.See our methodology
How Compounding Frequency Works
Compounding frequency determines how often interest is calculated and added to your balance. More frequent compounding means interest is calculated more often, which can slightly increase returns.
| Frequency | Compounds Per Year | Common Uses |
|---|---|---|
| Annually | 1 | CDs, some bonds |
| Quarterly | 4 | Many savings accounts |
| Monthly | 12 | Most loans, mortgages |
| Daily | 365 | High-yield savings, credit cards |
Important Considerations
- •Returns are not guaranteed: This calculator assumes a constant rate of return. Actual investment returns vary and can be negative.
- •Inflation reduces purchasing power: A 7% nominal return with 3% inflation provides only about 4% real growth.
- •Taxes affect your returns: Interest and investment gains may be taxable. Consider tax-advantaged accounts like IRAs and 401(k)s.
- •Fees reduce growth: Investment fees compound over time, reducing your final balance.
Frequently Asked Questions
What is a realistic rate of return to use?
Historical stock market returns have averaged around 7-10% annually before inflation, but past performance doesn't guarantee future results. Savings accounts and bonds typically offer lower, more predictable returns. Consider using conservative estimates for long-term planning.
How does compound interest differ from simple interest?
Simple interest is calculated only on the original principal, while compound interest is calculated on the principal plus any accumulated interest. Over time, compound interest generates significantly more growth.
Should I prioritize paying off debt or investing?
This depends on your specific situation, including interest rates, tax implications, and financial goals. Generally, high-interest debt (like credit cards) should be prioritized. Consider consulting a financial advisor for personalized guidance.
This calculator provides estimates for educational purposes only. It is not financial advice. Consult a qualified financial advisor before making investment decisions.Learn more about our methodology.