What is a return on investment?

Investing centers around making gains off of your initial capital. When determining the potential gains one could make there are a number of variables one needs to consider, such as how much capital one has put into the investment and what returns are associated with that asset class.

This led to the creation of ROI (return on investment), a measure that allows anyone to calculate the net profit or loss of an investment in percentage form. 

What is return on investment?

All investments, including stocks, bonds, real estate, and small businesses, come with the goal of making more money than you put in. The money you earn over and above your initial investment is called profit. When discussing investment profitability, people often use the term ROI, meaning return on investment. This metric expresses the amount of net profit one can earn/earned as a percentage of what the initial investment was.

ROI can help you assess if buying property or investing in a business is worth it. It's also helped companies determine the value of adding new products, building more facilities, acquiring other businesses, advertising campaigns, etc.

ROI (return on investment) is the percentage of gain or loss on an investment relative to the total cost of the investment.  In other terms, it's a way to compare different investments in order to figure out which ones are worth pursuing. For example, you could calculate ROI to decide whether selling one stock and buying another would be a good idea.

While there is no limit to a return on investment theoretically, in practice, no investment is guaranteed to have any return. If your ROI is negative, it means you not only failed to make a profit but also lost some of your original investment. The worst possible outcome would be -100% ROI, meaning you completely lost your initial investment. An ROI of 0% signifies that you at least recovered the money you put in, but gained nothing beyond that.

While ROI is often used as a marker of profitability, it isn't foolproof. There are several limitations to calculating ROI as your only measure which include the time frame in which you will earn back your investment, inflation rates, how risky a venture is, and additional maintenance costs that may be incurred.

Calculating ROI terminology

Before we dive in, let's first cover some basic terminology.

Net profit or net income

Net profit is the amount of money left over after all operating costs, such as the cost of transaction costs or maintenance costs, and other expenses have been accounted for and subtracted from the total revenue. It is used to measure profitability. Net profit can also be called net income, net earnings, or the bottom line.

Total cost of investment

This figure will look at the amount of money invested in a particular investment.

How to calculate ROI: the ROI formula

The ROI formula is a simple equation that looks at the price change of the asset and the net profits (the initial cost of the investment minus its value when you sell it). When calculating ROI you would use this formula:

ROI = (Net Profit / Total Cost of Investment) x 100

To factor trading costs into your ROI figure, you'll use: 

ROI = ((Value of Investment - Cost of Investment – Associated Costs) / Cost of Investment) x 100

As an example, let's say you buy 5 shares of $100 each in Twitter, equating to $500. You sell them a year later for $150 each, equating to $750. Let's say you paid $5 commission on each trade, costing you $25 in trading fees. 

ROI = (($750 - $500 - $25) / $500) x 100 = 45%

This means that you made a 45% return on investment on that particular investment.

How to determine a strong ROI

A "good" return on investment is any number above 0, as this means you made some profit. However, the ideal ROI should be higher than what you could've earned had you chosen another investment (the next best thing). 

To compare this, investors often compare their earnings to what they could've made on the broader stock market or in a high-yield savings account. Using the S&P 500 as a control, over the past four decades it has made gains of around 7% (after inflation). An ROI is generally considered to be a strong one if it beats the stock market in the long term. 

It's always important to note that past performance does not equate to future results. Another pearl of wisdom to remember is that high rewards generally come alongside high risks. If an investment promises very high ROIs, consider this also means that it comes with high risks. 

Therefore, a strong ROI will vary depending on the investment's level of risk, your goals, and how much risk you're willing to take.

Where the ROI formula falls short

The main limitation of using this return on investment ROI formula as a marker of success is that it doesn't show how long it took to earn the money back. When comparing various investments, the time it takes to mature will have a significant impact on the profits you could earn.

For instance, a year loan versus a bond held for five years versus a property held for 10 years will all have varying ROIs once you've established how long it will take to earn the specified ROIs. 

In this scenario, the ROI calculations mentioned above skimp on the full story. It also doesn't account for risk. For instance, the loan repayments could be delayed or the property market might be in a slump, all affecting the potential profits earnable.

With many variables, it becomes harder to predict what the exact ROI calculation on an investment will be, so be sure to factor this in when using the return on investment ROI formula to determine how attractive an investment opportunity or business venture is. 

ROI alternatives

Although the return on investment doesn't consider how long you keep an asset, it's essential to compare the ROI of investments held for comparable lengths of time as a more clear performance measure. If that's not possible, there are a few other options.

Average Annual Return

Also known as annualized return on investment, this adjusts the ROI formula to factor in the timing. Here you would divide the ROI by the number of years you hold the asset.

Compound Annual Growth Rate (CAGR)

This option is more complicated but yields more accurate results as it factors in compound interest generated over time. 

Internal Rate of Return (IRR)

This measure factors in the notion that profits earned earlier outway the same profits earned later, taking into account interest that could've been earned and factors like inflation. This equation is quite complicated but there are online calculators one can use. 

Conclusion

A return on investment (ROI) is a formula used to calculate the net profit or loss of an investment in percentage form. The ROI calculation can present valuable information when investing capital or determining profitability ratios. The ROI equation looks at the initial value of one investment and determines the financial return. A negative ROI indicates that the investment returns were lower than the investment cost.