What is an ROI calculator?
An ROI calculator estimates the financial return from an investment by comparing what you spend with what you gain or save. This calculator uses four inputs: one-off investment, running cost per month, extra revenue or savings per month, and the number of months you want to measure.
The result helps you compare options in practical terms. Net gain shows the total amount left after costs over the selected period. Return on investment shows that gain as a percentage of the upfront investment. Payback time estimates how many months it takes for monthly gains to cover the initial cost.
Use it for software purchases, process improvements, equipment, campaigns, or any project where you can estimate monthly savings or added revenue. The calculator is only as accurate as the numbers you enter, so it is best used for planning scenarios rather than as a guarantee.
How to use the ROI calculator
- Enter the one-off investment amount, such as setup, purchase, onboarding, or implementation cost.
- Enter the running cost per month, including subscriptions, maintenance, support, or recurring labor costs.
- Enter the extra revenue or savings per month you expect the investment to create.
- Choose the period in months you want to evaluate, such as 12, 24, or 36 months.
- Review the net gain, ROI percentage, and payback time, then adjust the inputs to compare best-case, expected, and conservative scenarios.
ROI calculator FAQ
How do you calculate ROI?
ROI is calculated by dividing net gain by the initial investment, then multiplying by 100. In this calculator, net gain is: monthly revenue or savings minus monthly running cost, multiplied by the number of months, minus the one-off investment. If the investment is zero, the ROI percentage is shown as 0 to avoid division by zero.
What is net gain in an ROI calculation?
Net gain is the amount left after subtracting both the upfront investment and recurring costs from the revenue or savings created over the period. This calculator uses: (monthly gain minus monthly cost) times months, minus the one-off investment. A positive net gain means the scenario earns or saves more than it costs over the selected period.
How is payback time calculated?
Payback time estimates how many months it takes for the monthly net benefit to recover the initial investment. The formula is: investment divided by monthly gain minus monthly cost. If monthly gain is not greater than monthly cost, payback time is shown as 0 because the investment does not pay back under those inputs.
What is a good ROI percentage?
A good ROI depends on the type of investment, risk, time period, and alternatives available. A short-term software investment may be judged differently from equipment, hiring, or marketing spend. Use the ROI percentage alongside net gain and payback time, and compare it with other realistic uses of the same budget.
Can I use this ROI calculator for cost savings instead of revenue?
Yes. The monthly gain field can represent either extra revenue or monthly savings. For example, if a tool reduces manual work, lowers vendor costs, or prevents recurring expenses, enter the estimated monthly savings as the gain. The calculation works the same way as long as the savings are realistic and tied to the investment.
Does the calculator include taxes, financing, or inflation?
No. This ROI calculator uses a simple planning model based on upfront investment, monthly cost, monthly gain, and period. It does not include taxes, depreciation, financing costs, inflation, or the time value of money. For major financial decisions, use it as a starting point and review the details with a finance professional.