ROI Calculator

Return on investment sounds simple until two numbers get mixed up: the total return and the yearly return. This ROI calculator gives you both. Enter what you paid in (the initial value) and what the investment is worth now (the final value), and it returns the total ROI as a percentage — (final − initial) / initial — together with the absolute profit or loss.

Add the holding period in years — decimals like 2.5 are fine — and the calculator annualizes the result into CAGR, the compound annual growth rate: (final/initial)^(1/years) − 1. CAGR is the honest way to compare investments held for different lengths of time, because a 100% gain means 14.87% a year over five years but barely 3.5% a year over twenty.

Whenever the growth rate is positive, you also get the doubling time in two flavors. The rule of 72 divides 72 by the rate in percent — the classic mental shortcut — and next to it stands the exact answer, ln 2 / ln(1 + r). At 14.87% the shortcut says about 4.84 years while the true value is 5.00, which is exactly the kind of gap the side-by-side view makes visible.

Values are plain numbers, so the calculator works with any currency, and losses are handled without sugarcoating: a final value below the initial one produces a negative ROI and CAGR, and the doubling time is marked as not applicable. Everything runs locally in your browser — nothing is uploaded, stored or sent anywhere.