$100 Invested at 9% for 3 Years
$130.86
Future Value (compounded monthly)
$100 invested at 9% annual compound interest (compounded monthly) for 3 years will grow to $130.86. You earn $30.86 in interest. At 9%, your money doubles in approximately 8 years (Rule of 72).
Year-by-Year Growth
| Year | Balance | Interest |
|---|---|---|
| 1 | $109.38 | $9.38 |
| 2 | $119.64 | $19.64 |
| 3 | $130.86 | $30.86 |
Quick Reference Table
| Principal | Rate | Years | Future Value |
|---|---|---|---|
| $100 | 7% | 3 yrs | $123.29 |
| $100 | 8% | 3 yrs | $127.02 |
| $100 | 10% | 3 yrs | $134.82 |
| $100 | 11% | 3 yrs | $138.89 |
| $100 | 9% | 1 yrs | $109.38 |
| $100 | 9% | 2 yrs | $119.64 |
| $100 | 9% | 5 yrs | $156.57 |
| $100 | 9% | 7 yrs | $187.32 |
| $100 | 9% | 10 yrs | $245.14 |
| $100 | 9% | 15 yrs | $383.80 |
Formula Used
A = P(1 + r/n)nt
- P = $100
- r = 9% = 0.09
- n = 12 (monthly)
- t = 3 years
- A = $130.86
Frequently Asked Questions
How much will $100 grow at 9% compound interest in 3 years?
$100 grows to $130.86. Interest earned: $30.86.
How long to double $100 at 9%?
Using the Rule of 72: 72 ÷ 9 ≈ 8 years.
What is the compound interest formula?
A = P(1 + r/n)^(nt). P=$100, r=9%=0.09, n=12, t=3.