The ROI formula is ROI% = (final value − initial cost) ÷ initial cost × 100, which expresses the net profit from any investment as a percentage of what you put in. With that single equation, you can line up a $500 stock trade, a $30,000 rental property, and a $2,000 marketing campaign on the same percentage scale. A free, no-sign-up ROI calculator handles the division, the percentage, and the net profit for you the moment you type in what you paid and what the investment is now worth. You can also add a holding period in years to get the annualized return, also called the compound annual growth rate (CAGR), which is the steady yearly rate that would turn your cost into the final value. Everything happens locally in your browser, so the numbers never leave your device, and you do not need to create an account, hand over an email address, or pay anything to see the result.
What the ROI formula actually does
The plain return-on-investment formula has three pieces: the cost you paid, the final value you received (or the current value if you have not sold yet), and the percentage that turns the difference between them into a comparable number. The equation is ROI% = (final value − initial cost) ÷ initial cost × 100. The companion figure, net profit, is simply final value − initial cost. Because everything is divided by the cost before being scaled to a percentage, a $500 gain on a $1,000 stake becomes 50%, and the same $500 gain on a $10,000 stake becomes 5% — a number you can put next to almost any other return without worrying about dollar size. The formula shows up across finance, marketing, and project management because it normalizes performance the way a percentage always does: relative to the base, not the absolute amount. ROI is treated as a gross measure, so it does not strip out fees, taxes, or inflation by default; for a deeper breakdown of the underlying math, the Wikipedia entry on return on investment walks through the same equation alongside its common variations.
Why plain ROI hides the time factor
Plain ROI has one well-known blind spot: it does not know how long you held the investment. A 50% gain looks identical whether it took one year or ten, even though those two outcomes feel very different in a portfolio. The fix is annualized ROI, which is the same thing as the compound annual growth rate (CAGR): the steady per-year rate that would turn your cost into your final value over the number of years you held it. The formula is ((final value ÷ cost)^(1 ÷ years) − 1) × 100. The exponent is what makes time appear in the result — by taking an Nth root, you compress the total gain back into a single yearly rate. A $1,000 to $1,500 trade in one year is a 50% plain ROI and also a 50% annualized ROI. The same $1,000 to $1,500 trade over three years is still 50% plain, but the annualized figure drops to about 14.47%, which is much closer to a savings-account rate or a long-term benchmark return. Without that adjustment, headline ROI percentages from short and long holdings are not directly comparable.
Calculate your ROI in three steps
- Type the initial cost — the total dollars you paid for the investment, including any commissions or buy-in amounts rolled into the price.
- Type the final value — what the investment is worth right now, or what you sold or liquidated it for if you have already exited.
- Read the ROI percentage and net profit that appear immediately below the inputs; if you also want the annualized return, add the holding period in years and watch the CAGR line update at the same time.
You can change either number as many times as you want, and the result updates as you type. A free ROI calculator that does not require sign-up keeps the workflow to exactly those three fields for plain ROI, with the holding period as an optional fourth input for annualized returns.
Reading the output: percentage, profit, and annualized return
The plain-ROI line tells you the percentage gain or loss relative to what you put in. A positive number means you made money, zero means you broke even, and a negative number means you lost money — for example, a $2,000 cost that ends at $1,600 is a −20% ROI and a $400 loss. The net-profit line simply restates the same information in dollars, which is useful when you want to know the absolute size of the gain alongside the percentage. The annualized ROI line, when you supply a holding period, converts the total gain into a per-year rate. Worked example: you buy $10,000 of an asset and sell it for $20,000 after ten years. Plain ROI is (20,000 − 10,000) ÷ 10,000 × 100 = 100%, a $10,000 profit. Annualized ROI is ((20,000 ÷ 10,000)^(1 ÷ 10) − 1) × 100 = (2^0.1 − 1) × 100 ≈ 7.18% per year, because that 100% was spread across a decade. If you want a different walk-through of the same inputs and outputs, the step-by-step ROI walk-through covers the same flow with a slightly different framing.
Where the ROI number can mislead
The percentage you see is gross ROI: it uses only what you paid and what the investment is now worth, and it assumes the gain is fully realized. It does not subtract trading commissions, fund expense ratios, capital-gains taxes, brokerage fees, or the inflation that erodes a future dollar's purchasing power. It also does not charge you for the opportunity cost of having money tied up in this investment instead of another. For short holding periods on a taxable account, those omissions can change the final number by a few percentage points; for long holding periods in a high-fee product, they can flip a positive headline ROI into a real loss. Treat the result as a fast estimate, then verify with a tool that knows about fees, taxes, or scheduled deposits. For interest that compounds on a starting balance plus regular contributions, a savings calculator handles the contribution and interest split; for a fixed-rate loan or bond yield, a simple interest calculator covers the non-compounding case.
Comparing ROI across investments side by side
Because plain ROI and annualized ROI answer different questions, it helps to keep both on the page when you line up two or more investments. The table below summarizes the difference at a glance, without picking specific dollar amounts so you can run any scenario through the tool yourself and see both numbers side by side.
| Feature | Plain ROI | Annualized ROI (CAGR) |
|---|---|---|
| Inputs required | Cost and final value | Cost, final value, and a holding period in years |
| What it expresses | Total percentage gain or loss over the whole holding period | Steady per-year rate that turns cost into final value |
| Time awareness | Ignores how long the investment was held | Adjusts the result for the length of the holding period |
| Best for | Quickly comparing two outcomes of similar length | Comparing an investment to a savings rate, index fund, or other long-horizon benchmark |
| Watch out for | Headline percentages from very different timelines can look the same | Final value must be positive and holding period must be above zero |
| Includes fees and taxes | No — gross return only | No — gross return only |
Run the same two investments through the tool with and without a holding period, and the gap between plain and annualized ROI is usually the clearest signal of how much time is doing in your headline number.
For a deeper look, see Savings Calculator Free No Sign Up Needed.