What happens to $100,000 at 3% over 10 years?
If you invest $100,000 today at a 3% annual interest rate and leave it untouched for 10 years — with interest compounding annually — you end up with $134,391.64. That means your original principal earns $34,391.64 in compound interest, bringing your total return to 34.4% over the investment period.
The key driver is compounding: each year you earn interest not only on your original $100,000, but also on all the interest that has accumulated in prior years. In year one you earn $3,000.00, but by year 10 that annual interest payment grows to $3,914.32 — the same percentage applied to a much larger base.
At 3%, money doubles approximately every 23.4 years (Rule of 72: 72 ÷ 3 = 24.0). Over a 10-year horizon that translates to a 1.34x growth multiple.
These figures assume a constant 3% rate, annual compounding, and no withdrawals or additional deposits. Use the interactive calculator below to model monthly contributions, different compounding frequencies, or any custom scenario.