Content reviewed: 24 September 2026

Measuring gain and simple return on investment

This calculator compares an initial investment with its final value. It reports the gain or loss and the simple return on investment (ROI) as a percentage of the initial amount.

Formula

Gain = Final value − Initial investment
ROI % = Gain ÷ Initial investment × 100

Example

If 10,000 becomes 12,500, the gain is 2,500 and the simple ROI is 25%.

What ROI does not tell you

A 25% return over one year and a 25% return over ten years are very different. This calculator does not annualise the result, and it does not account for deposits, withdrawals, dividends, fees, tax or inflation. Those factors can materially change investment performance.

Use the Compound Interest Calculator when you want to model growth over time at an assumed annual rate.