What happens to $100,000 at 5% over 20 years?
If you invest $100,000 today at a 5% annual interest rate and leave it untouched for 20 years — with interest compounding annually — you end up with $265,329.77. That means your original principal earns $165,329.77 in compound interest, bringing your total return to 165.3% 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 $5,000.00, but by year 20 that annual interest payment grows to $12,634.75 — the same percentage applied to a much larger base.
At 5%, money doubles approximately every 14.2 years (Rule of 72: 72 ÷ 5 = 14.4). Over a 20-year horizon that translates to a 2.65x growth multiple.
These figures assume a constant 5% 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.