Compound Interest Calculator
Convert and compare interest rates between different compounding periods. Use our Interest Calculator for actual compound interest calculations.
Interest Rate Converter
Compare equivalent interest rates across different compounding periods
Quick Comparison
See how a 6% interest rate compares across different compounding frequencies:
| Compounding Frequency | Periods per Year | Effective Annual Rate |
|---|---|---|
| Annually | 1 | 6.0000% |
| Semiannually | 2 | 6.0900% |
| Quarterly | 4 | 6.1364% |
| Monthly | 12 | 6.1678% |
| Weekly | 52 | 6.1800% |
| Daily | 365 | 6.1831% |
| Continuously | ∞ | 6.1837% |
Related Calculators
What is Compound Interest?
Interest is the cost of using borrowed money, or the amount a lender receives for advancing money to a borrower. Interest can be categorized as either simple interest or compound interest.
Simple interest is calculated only on the principal amount. For example, $100 at 10% simple interest for 2 years:
$100 × 10% × 2 years = $20
Compound interest is calculated on both the principal and accumulated interest. Using the same example:
The power of compound interest becomes more dramatic over longer periods. A $1,000 investment at 10% annual return for 45 years would grow to approximately $72,890!
Different Compounding Frequencies
Interest can compound at different frequencies, affecting the total interest earned or owed:
- Annual: Interest compounds once per year
- Semiannual: Interest compounds twice per year
- Quarterly: Interest compounds four times per year
- Monthly: Interest compounds twelve times per year
- Daily: Interest compounds 365 times per year
- Continuous: Interest compounds infinitely often
More frequent compounding generally results in higher effective rates, but the difference becomes marginal as frequency increases beyond daily compounding.
Compound Interest Formulas
Basic Compound Interest
General Compound Interest Formula
Continuous Compound Interest
Rule of 72
The Rule of 72 is a quick way to estimate how long it takes for an investment to double:
For example, at 8% annual return: 72 ÷ 8 = 9 years to double your money.
Note: This is an approximation and works best for rates between 6% and 10%.