Return on Investment (ROI) is the ratio of the profit (or return) for a web site, divided by the cost of the site, multiplied by 100 to express as a percentage.

Think of ROI as "bang for your buck". What are you going to get or achieve by having your client spend money on a project.

ROI is calculated over a defined period.

The actual calculation for ROI is trivial, but figuring out your return and your investment may not be so easy.

There are many factors to consider when developing an ROI calculation. Like any calculation, it is difficult to come up with a qualitative metric.