ROI Calculator

Written byOleh Soloninupdated 5 October 2026

Currency

Amount invested

Amount returned

Period, months

Advanced options

Extra costs

Fees, taxes and other costs, added to the amount invested.

Inflation, % a year

For the real return.

Alternative, % a year

Such as a savings rate: what the same money would earn over the same time.

Result

Profit

$1,500.00

ROI, %

15%

Annualised, %

9.77%

Working

ROI = (11,500.00 − 10,000.00) ÷ 10,000.00 × 100 = 15% A year = (11,500.00 ÷ 10,000.00)^(12 ÷ 18) − 1 = 9.77%

The same ROI per year over other terms

      Term      A year
      6 mo      32.25%
     12 mo         15%
>    18 mo       9.77%
     24 mo       7.24%
     36 mo       4.77%
     60 mo       2.83%

This result is informational only and is not professional advice.

ROI as a percentage, the return per year, and a comparison with an alternative

Return on investment with the formula worked through: profit and ROI as a percentage, the annualised return with compounding, extra costs, the real return after inflation, a comparison with an alternative rate and the same ROI per year over other terms.

ROI, return on investment, shows the profit as a percentage of what you put in: (amount returned − amount invested) ÷ amount invested × 100. The calculator works it out with your numbers and converts it to a yearly return so investments of different lengths can be compared.

In the extra settings you can add costs such as fees and tax, see the return after inflation, and compare the result with an alternative, such as a savings account at a known rate.

How to use

Enter the amount invested, the amount you got back including profit, and how many months it took.
In the extra settings add costs, inflation and an alternative rate.
Read the profit, the ROI, the yearly return, the Working lines and the table for other terms.

The ROI formula

ROI = (returned − invested) ÷ invested × 100%. Invest 10,000 and get back 11,500 and the profit is 1,500, an ROI of 1,500 ÷ 10,000 × 100 = 15%. Costs such as fees or tax are added to the amount invested. A loss gives a negative ROI.

For advertising, enter the spend plus the profit from the extra sales as the amount returned, not the revenue: ROI measures profit.

ROI as an annual return

ROI ignores time: 15% over one year and over five years look the same. To compare, convert it to a yearly rate with compounding: (returned ÷ invested)^(12 ÷ months) − 1. 15% over 18 months is 9.77% a year, not 10%, because the second stretch earns on a bigger amount.

10,000 invested, 11,500 returned. Worked out with this calculator.
Term	15% ROI per year
6 months	32.25%
12 months	15%
18 months	9.77%
24 months	7.24%
36 months	4.77%
60 months	2.83%

Real return and alternatives

The real return is (1 + nominal) ÷ (1 + inflation) − 1, not a simple subtraction: 9.77% a year with 3% inflation is 6.57% in real terms. Enter an alternative rate and the calculator shows what the same money would have reached over the same time: 10,000 at 4% for 18 months reaches 10,605.96, so an 11,500 return is 894.04 ahead. It does not weigh the difference in risk.

What this calculator shows

Profit and ROI as a percentage, with the formula
The annualised return with compounding
The real return after inflation
A comparison with an alternative over the same time
The same ROI as a yearly rate over other terms

What to keep in mind

One amount invested and one amount returned; for regular income and payback periods, use the payback period calculator.
Costs are added to the amount invested at the start.
The alternative compounds at the rate entered; risk is not included.

FAQs

What is the formula for ROI?

ROI = (amount returned − amount invested) ÷ amount invested × 100%. 10,000 invested and 11,500 returned is a 15% ROI. Add any costs to the amount invested.

How do I annualise ROI?

(Returned ÷ invested)^(12 ÷ months) − 1. A 15% ROI over 18 months is 9.77% a year; over 36 months it is 4.77%.

How do I adjust ROI for inflation?

Real return = (1 + nominal) ÷ (1 + inflation) − 1. 9.77% with 3% inflation is 6.57%, slightly less than simple subtraction suggests.

Can ROI be negative?

Yes. If you invest 10,000 and get back 9,000, the ROI is −10%.

How do I calculate ROI on advertising?

Use the profit from the extra sales, not the revenue: ROI = extra profit after all costs, the ad spend included, ÷ ad spend × 100. Enter the spend plus that profit as the amount returned.

What counts as a good ROI?

Only against an alternative and a period. The default figures here — 10,000 invested, 11,500 back after 18 months — give 15%, but stretched over a year and a half that is 9.8% a year, which is a different sentence entirely. Enter the alternative rate and the inflation figure to see what survives of it.

Worked example

18 months

Input: 10,000 invested, 11,500 returned after 18 months, 3% inflation

Output: Profit 1,500, ROI 15%, 9.77% a year

Note: After inflation that is 6.57% a year; 4% a year would have turned the same 10,000 into 10,605.96.

Useful links

All tools in Finance calculators for loans, mortgages, interest, and everyday money checks

ROI Calculator

Result

Related tools

Payback Period Calculator

Investment Calculator

Break-Even Calculator

Compound Interest Calculator

Useful links