Roo Calculator
Roo calculator works out Net gain or loss and Return on investment from Amount invested (initial cost), Final value and Holding period. The default figures on this page give return on investment of 20.0000 %; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
2 steps
- Net gain = 1200 - 1000 = 200
- ROI = 100 x 200 / 1000 = 20%
Its 5 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
4 sources
Keep this result
Save it, change one figure, then compare the two
The calculation stays free. Save this scenario, adjust one assumption, save that too, and put them side by side to see exactly what the change costs you. A free account keeps 5 scenarios and 2 comparisons; Personal makes both unlimited and adds exports and private links. Nothing is saved unless you press Save.
What the roo calculator calculates
Computes the net gain and percentage return on an investment from its cost and final value, the price and total return of a share holding including dividends, and total shareholder return, with an optional annualised equivalent.
How to use this roo calculator
Enter Amount invested (initial cost), Final value and Holding period. Net gain or loss updates as you type. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Net gain or loss, Return on investment and Price return.
The method follows Return on investment: ROI = (final value - cost) / cost, Holding period return of a share: price return and total return including distributions, Total shareholder return: TSR = (ending value + distributions - beginning value) / beginning value and CFA Institute, Rates and Returns - holding period return and the geometric mean.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
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Frequently asked questions
What information do I need for the roo calculator?
You need Amount invested (initial cost), Final value and Holding period. The page opens with default figures that give return on investment of 20.0000 %, so you can see the scale before entering your own.
What does this roo calculator show?
It shows Net gain or loss, Return on investment, Price return, Total return, Total shareholder return, Annualised equivalent, Growth multiple and What the return was measured on, with the working and any warnings for your entries.
Can I check how the roo calculator result was calculated?
Yes. The “How this is worked out” section shows the calculation steps, and the sources section identifies the references used for the method.