How this calculator works
An HR system is worth buying when the value of the time and money it frees up exceeds what it costs. The costs are usually a mix of one-time and recurring items. Implementation, training and a licence are paid once; subscription fees, hosting and support recur every year. The benefit comes from staff spending less time on administration such as leave requests, onboarding paperwork and payroll corrections. Multiply the hours saved per employee per year by the number of employees and by the fully loaded hourly cost of an employee, which should include salary and benefits, not just the wage. Add any other savings, such as fewer payroll errors or lower spending on stationery. Return on investment is the net benefit divided by the total cost over the period. The payback period answers a different question: how long before the cumulative benefit covers the one-time cost plus the recurring fees run so far. A system with a high three-year return can still have a long payback if the implementation is expensive, which matters for a business that may change direction. The estimates rest on the hours-saved assumption, which is the least reliable input. Ask the vendor for customer references, and pilot the system with one team before committing.
Formula
One-time cost = implementation + training + licence (when licensed). Recurring cost = subscription (when subscribed) + hosting and support. Total cost = one-time cost + recurring cost x years. Annual benefit = employees x hours saved per employee x fully loaded hourly cost + other annual savings. Total benefit = annual benefit x years. Return on investment = (total benefit - total cost) / total cost. Payback, in months, = one-time cost x 12 / (annual benefit - recurring cost).
Worked example
A three-year subscription at $12,000 a year, with $15,000 of implementation, $5,000 of training and $6,000 a year of support. The one-time cost is $20,000 and the recurring cost is $18,000 a year, so the three-year cost is $74,000. With 250 employees saving 2.5 hours a year at a loaded cost of $35 an hour, the time saved is worth $21,875 a year, and $8,000 of other savings brings the annual benefit to $29,875, or $89,625 over three years. The net benefit is $15,625, a return of 21.1% over three years, or about 7.0% a year. Payback is $20,000 x 12 / ($29,875 - $18,000) = 20.2 months.
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Frequently asked questions
Should the labour saving be counted at the full salary?
Use the fully loaded hourly cost of the employee whose time is freed. If the saved hours are not redeployed to useful work, the benefit is smaller than the formula suggests. Many projects overstate this line.
What if the software replaces a role entirely?
Count the avoided salary and benefits, including recruitment and training costs, and treat it as a saving only when the role is actually removed or not filled. Counting a saving while keeping the person is a bookkeeping illusion.
How do I choose the evaluation period?
Long enough to include the implementation year and at least two years of steady operation, which is usually three to five years. A one-year view makes almost any implementation look bad because the one-time costs land in it.
Why is the payback period useful alongside ROI?
ROI says whether the project is worth doing over the whole period. Payback says how long the business is exposed before the cash comes back. A project can have a good ROI and an uncomfortable payback.
Should I discount future benefits?
For a large decision, yes. A dollar saved in three years is worth less than a dollar today. Use a discount rate in line with the cost of capital, and treat the undiscounted figure here as a first screen.