Continuous Compounding Calculator
How to use the tool
Step-by-step
- 1. Type your nominal annual rate as a plain number—e.g., 3.2 or 9.4.
- 2. Enter the investment length in years; decimals handle partial years—e.g., 8.5 or 4.2.
- 3. Add the starting principal without commas—e.g., 2500 or 7500.
- 4. Press “Calculate” to see the continuously-compounded effective rate and final amount.
Field-input examples
- Example 1: Principal = 2 500, Rate = 3.2, Time = 8.5 → Final ≈ $3 174.22; Continuous rate ≈ 3.25 %.
- Example 2: Principal = 7 500, Rate = 9.4, Time = 4.2 → Final ≈ $11 683.29; Continuous rate ≈ 9.80 %.
Formula applied
The calculator uses the continuous-compounding model
$$A = P\,e^{rt}$$
where P is principal, r the nominal rate as a decimal, and t time in years (NIST Digital Library, 2020).
Quick-Facts
- Mathematical constant e ≈ 2.71828 (NIST Digital Library, 2020).
- Effective annual rate under continuous compounding equals (e^{r}−1) (Investopedia, 2023).
- “Double precision supports up to 15 decimal digits” (IEEE 754-2019).
- A 1-percentage-point rate rise over 30 years adds ≈ 30 % to the final sum (FRBNY Q2 2021).
FAQ
What is continuous compounding?
You earn interest every instant, so interest itself earns interest; it is the limit of faster compounding (Investopedia, 2023).
Why does it beat daily compounding?
The formula (e^{r}−1) always exceeds ((1+r/365)^{365}−1); at 10 % nominal the gap is ≈ 0.13 % (SEC Investor.gov, 2022).
How do I convert a nominal rate to a continuous rate?
Use (r_c = ln(1+r_{nom})); 6 % nominal becomes 5.825 % continuous (NIST Digital Library, 2020).
Is the calculator reliable for long terms?
IEEE 754 double precision handles exponents up to 10308, far beyond any practical horizon (IEEE 754-2019).
Can I apply these results to loans?
Few lenders charge continuous interest; most use daily or monthly schedules, so use results as theoretical benchmarks (FDIC Consumer Guide, 2021).
How are fractional years treated?
The exponent (rt) scales linearly; entering 3.75 years computes exactly four months past the third year (NIST Digital Library, 2020).
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