ROI Calculator

This ROI calculator turns two numbers, what you put in and what came back, into a percentage, then adds the annualized rate so you can compare deals that ran for different lengths of time. The example loaded on this page turns $1,000 into $2,000 over 2.5 years: a 100% return on investment, or 31.95% a year once the time is folded in. Enter your own figures, or switch to the date mode and let the calculator work out the length from a start and end date.

The formula

ROI is profit divided by cost, written as a percentage. Profit is whatever came back minus whatever went in, and the denominator is the money you committed.

ROI = (amount returned − amount invested) ÷ amount invested

Take a small workshop that buys a $50,000 machine and sells it four years later, having collected $70,000 of extra profit along the way and from the sale. The gain is $20,000, the cost is $50,000, and the ROI is 40%. Run it backwards and the formula answers a different question: if you want a 40% return on a $50,000 outlay, you need $70,000 back. That reversibility is why ROI gets scribbled on the back of an envelope more than any other finance number.

Why the annualized rate matters more

Plain ROI has no clock in it, which makes it useless for comparing two investments of different lengths. Annualized ROI fixes that by turning the total into a compound yearly rate.

Annualized ROI = (amount returned ÷ amount invested)^{1 ÷ years} − 1

Here is the trap in numbers. A rare coin returns 1,000% and a parcel of land returns 50%. The coin looks ten times better until you learn the coin took 50 years and the land took six months. Annualized, the coin earned 4.91% a year and the land earned 125%. The loaded example on this page shows the same effect in a milder form: a 100% return sounds enormous, and at 2.5 years it works out to 31.95% a year, which is excellent but no longer otherworldly. Whenever two options have different holding periods, compare the annualized figures and ignore the headline.

Deciding what counts as cost and what counts as gain

The formula is trivial; agreeing on the two inputs is where ROI goes wrong. Take a stock bought for $10,000 and sold for $13,000. The headline ROI is 30%. Now add $60 of commissions and a 15% long-term capital gains tax on the $3,000 profit, which is $450. The realized gain drops to $2,490 and the ROI to 24.9%. Neither number is dishonest; they answer different questions.

Problems start when two options get measured differently. One analyst prices a rental property using purchase price alone while another includes closing costs, the new roof, and property tax, and their ROIs are no longer comparable. Pick one definition, write it down, and apply it to every option on the list. For anything with money moving in and out over several years, simple ROI stops working entirely, because it cannot tell whether a dollar arrived in year 1 or year 9. That is what the IRR Calculator is for.

ROI, ROR, CAGR, and IRR

Four measures get used for the same job, and each answers a narrower question than the last:

• ROI is total profit over total cost, with no time dimension. Best for a quick screen or a single closed deal.
• Rate of return (ROR) is usually quoted for a stated period, most often a year, which is the difference people miss when they swap the terms.
• CAGR is the compound annual growth rate, the same arithmetic as the annualized ROI above, and it assumes one amount in and one amount out.
• IRR handles a whole stream of cash flows at different dates, which is what you need for a rental property, a business project, or a fund with capital calls.

Payback period sits alongside them and answers a question none of the four do: how long until the money comes back. A $50,000 machine that saves $20,000 a year pays back in 2.5 years, and the Payback Period Calculator handles the uneven cases.

ROI on marketing spend

Marketing borrows the same formula but usually reports ROAS, return on ad spend, which is revenue divided by spend rather than profit divided by cost. Spend $10,000 and drive $40,000 of revenue and the ROAS is 4:1, quoted as 400%. True ROI on that campaign is much lower, because revenue is not profit. If the goods cost 60% of revenue, gross profit is $16,000, and ROI on the ad spend is (16,000 − 10,000) ÷ 10,000, or 60%.

The harder problem in marketing is attribution. A customer sees a paid ad, ignores it, arrives through search two weeks later, and buys. Whichever channel gets credit posts a flattering ROI and the other looks like a waste. Brand campaigns are worse still, since the return arrives as recognition that shows up in sales months later. Where a direct number is not available, the usual approach is to measure the lift against a holdout region or a period with the spend switched off.

ROI on property and business projects

Property investors rarely stop at ROI, because a building generates rent every month and a lump sum at the end. Cap rate divides net operating income by the price and describes the building without the mortgage; cash-on-cash return divides annual cash flow by the cash you actually committed. Both are annual figures, so they sidestep the timing problem that plain ROI has. The Rental Property Calculator produces all of them alongside IRR.

Inside a business the same split shows up as return on invested capital and return on equity, and the reason is worth understanding: borrowed money shrinks the denominator. Put $46,000 of your own cash into a $200,000 asset and your percentage return moves several times faster than the asset's, in both directions.

What ROI does not tell you

ROI ignores risk completely. A 40% return on a Treasury-backed position and a 40% return on a single early-stage startup are the same number attached to wildly different odds, and no version of this formula will separate them. It also ignores inflation: a 25% return over five years is about 4.6% a year, which barely clears 3% inflation and leaves far less than it first appears. It says nothing about liquidity either, and it has a floor. Lose everything and ROI is -100%; only borrowed money can take you past that.

For context, the S&P 500 has returned roughly 10% a year over the long run before inflation and about 7% after it, while a strong savings account pays around 4% with no volatility at all. Any projected ROI far above those numbers is quoting either extra risk or a shorter window, and it is worth working out which. The Investment Calculator and the Average Return Calculator put a plan on that timeline.

Reading the two charts

The donut splits the ending value into the money you put in and the profit on top, so the loaded example reads 50% and 50%: half of the $2,000 is the original $1,000. If the amount returned is lower than the amount invested, the chart flips and shows what survived against what was lost. The area chart draws the balance compounding at the annualized rate from the first day to the last, with a dashed line at your original stake. The gap between the two lines at any point is the profit earned to that date, and it widens as it goes, because each year's growth builds on the last.