ROI Calculator

What ROI is for

ROI Calculator is the page to open when you need roi from measurements you already have. It belongs with the other financial calculators because that is the work this arithmetic supports. Type the entries first. The result stays hidden until you press Calculate, so a half-finished form never flashes a number you might mistake for the answer.

How to fill in this calculator

1. Initial Investment. Enter the value this part of the job needs.
2. Amount Returned. Enter the value this part of the job needs.
3. Investment Length. Enter the value this part of the job needs. The unit list on this field includes days, weeks, months, years.

The formula in plain language

The ROI result is the standard relationship for this job, applied to the numbers you type and the units on those fields. Loan and interest math here is the standard textbook formula. It is a planning figure, not a lender's offer. Fees, insurance, and a rate that changes will move the real payment. Compare two options with the same term and the same fees included. A lower payment that lasts many more months can cost more in interest.

A worked example

Suppose Initial Investment is 12 and Amount Returned is 8, in the units already selected on those fields. Press Calculate and write down the roi result. Change only Initial Investment to 24 and calculate again. If the result scales the way the formula says it should, the page is reading the form the way you intended. If it jumps by a factor of twelve, the unit on that field is still set to inches while you were thinking in feet, or the other way around.

Margin, return, and growth describe the same business decision. This ROI figure belongs with compound annual growth rate and WACC.

Mistakes that move the answer

• Leave the unit selector on the unit you actually measured.
• Press Calculate only after every required field is filled. An empty field is not a zero unless you typed zero.
• Round the result to the precision you can buy or build. Extra decimals do not make a tape measure more accurate.

How to check the result

After Calculate shows the roi result, redo the last operation with a pencil using the rounded figures on the screen. Matching that check means the inputs were read correctly. If you edit a label or a sentence in this HTML file, reload the page. The form and this article both live in the file, so the edit is what visitors will read.