ROI Calculator

The ROI calculator is a free tool that runs entirely in your browser, with no data ever sent to a server. Work out a return on investment and its annualised rate.

The formula

Return on investment compares the net gain with the amount committed: (amount returned − amount invested) ÷ amount invested. Multiplied by a hundred, it reads as a percentage. Getting back €13,500 after investing €10,000 gives an ROI of 35 %.

Why the duration changes everything

An ROI of 35 % earned in six months has nothing in common with the same figure spread over ten years. The annualised return brings the operation back to a yearly basis, compounding included: it is the only figure that lets you compare two investments of different lengths.

What the number leaves out

Raw ROI ignores inflation, tax, management fees and the risk taken. Two operations showing the same return can be radically different if one is guaranteed and the other exposed to a total loss.

What this tool does not do

This tool computes a return from two amounts: it models neither staggered payments, nor intermediate withdrawals, nor dated cash flows. It is not investment advice.

Frequently asked questions

What does a negative ROI mean?

That you got back less than you put in. An ROI of −20 % means a fifth of the invested capital was lost on the operation.

How does it differ from IRR?

The internal rate of return accounts for the date of every movement of money, which ROI ignores. For an investment with regular payments, IRR is far more accurate, but it needs a full table of cash flows.

Is my data sent to a server?

No: the text you type or paste is processed entirely in your browser, on your device. It is never transmitted to a server.

Do I need an account or an install?

No: the tool works directly on this page, with no sign-up and no installation.