ROI
calculator
Put money in, got money out, what was the return? ROI turns any investment into a clean percentage, and with a holding period it becomes an annualized rate you can compare against anything else.
Prefer a physical calculator?
A few solid picks. As an Amazon Associate, Calculate.to earns from qualifying purchases, at no extra cost to you.
OSALO Desktop Calculator
Extra-large 12-digit LCD, giant buttons, solar + battery, the classic office desk workhorse.
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Helix Oxford Scientific
240-function scientific calculator for KS3–KS4 maths, with hard cover. Exam-friendly, plastic-free packaging.
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Casio fx-83GTCW+
The UK classroom-standard scientific calculator (also in pink), allowed in most UK exams.
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ROATEE Construction Calc
Feet-inch-fraction engineering calculator for carpenters, framers and contractors on site.
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Return on investment, properly
ROI is profit relative to what you paid: the gain divided by the cost, as a percentage. It works for anything, shares, property, a business project, a course, which is exactly its strength and its trap.
Worked example
Over 3 years, annualized: 1.5^(1/3) − 1 ≈ +14.5%/yr
The trap: ROI ignores time
A 50% ROI is superb in one year and mediocre over fifteen. Always pair ROI with the holding period, the annualized figure (which is just CAGR) is the number that lets you compare a property flip with an index fund. And remember to count all costs: fees, taxes and your own time all belong in "invested".
ROI FAQ
Subtract the amount invested from the final value, divide by the amount invested, and multiply by 100. Turning $5,000 into $7,500 is a 50% ROI.
It depends entirely on the timeframe and risk. As a reference point, the US stock market has averaged about 10% a year long-run, so judge any ROI against its holding period, annualized, not as a raw total.
ROI is the total return over the whole period; CAGR spreads it into an equivalent yearly compound rate. A 50% ROI over 3 years is about 14.5% CAGR.
Yes, the honest 'invested' figure includes purchase costs, fees, taxes and improvements. Leaving them out inflates the ROI.