TCO Worked Examples and Selection Checklists
ERP ROI and payback: how to estimate efficiency savings honestly
How to estimate measurable ERP savings in staff time, inventory, write-offs and compliance work, calculate payback and ROI, and avoid inflated business cases.
An ERP pays back when the measurable yearly savings, minus the yearly running cost, add up to the one-time cost of the project. The calculation itself is simple; the hard part is estimating savings you can actually measure and attribute to the new system. Count staff hours you will genuinely redeploy, lower inventory holding, fewer write-offs and errors, faster collections and less outside compliance work. Leave out vague benefits such as "better decisions" from the payback sum. This guide shows the method with illustrative rupee figures, and the ERP payback calculator does the arithmetic for you.
This guide belongs to the 3–5-year ERP TCO guide section.
The formulas
- Net yearly saving = gross measurable savings − yearly subscription, support and other running costs of the new system + running costs of the old system you stop paying.
- Payback period = the point at which cumulative net yearly savings equal the net one-time cost (one-time cost − any grant actually sanctioned).
- Simple ROI over N years = (total net savings over N years − net one-time cost) ÷ net one-time cost × 100.
Where savings really come from
| Saving | How to measure it | Typical evidence | Pitfalls |
|---|---|---|---|
| Staff time | Hours a week on data entry, re-keying, reconciliations, report compilation | Time log for two to four weeks before the project | Saved hours are only a saving if the person moves to other useful work or a vacancy is not filled |
| Inventory holding | Average stock value × holding cost rate (interest, storage, damage) | Stock reports, bank interest rate | Stock falls only if purchasing actually changes |
| Write-offs | Expired, damaged or lost stock per year | Write-off entries in past accounts | Some write-offs have causes the software cannot fix |
| Collections | Reduction in average debtor days × daily sales × cost of funds | Debtor ageing reports | Depends on credit discipline, not just software |
| Compliance work | Fees or overtime for GST reconciliation, e-invoicing, TDS returns | Invoices from consultants, overtime records | You may still need a CA for review |
| Errors and penalties | Late fees, interest and penalties paid in past years | GST and TDS payment history | Past penalties may have had one-off causes |
| Old system costs | Licences, AMC, servers, add-ons you will retire | Contracts and invoices | Keep the old system read-only for a while: it may still cost something |
Worked example (illustrative)
A trading company with ₹25 crore turnover plans an ERP with a one-time cost of ₹15,00,000 (implementation, migration, training, contingency). The new system costs ₹6,50,000 a year to run; it replaces software and AMC costing ₹1,50,000 a year.
Gross measurable savings per year
| Saving | Calculation | Amount |
|---|---|---|
| Staff time | 1.5 full-time roles not refilled after natural attrition × ₹4,00,000 | ₹6,00,000 |
| Inventory holding | Stock down ₹30,00,000 × 12% holding cost | ₹3,60,000 |
| Write-offs | Expired stock down from ₹4,00,000 to ₹2,00,000 | ₹2,00,000 |
| Outside reconciliation work | Reduced consultant fees | ₹1,00,000 |
| Total gross savings | ₹12,60,000 |
Net yearly saving = ₹12,60,000 − ₹6,50,000 + ₹1,50,000 = ₹7,60,000.
Payback: assuming savings start in full in year 1, ₹15,00,000 ÷ ₹7,60,000 ≈ 2.0 years.
Five-year ROI (no growth): (₹7,60,000 × 5 − ₹15,00,000) ÷ ₹15,00,000 × 100 = (₹38,00,000 − ₹15,00,000) ÷ ₹15,00,000 × 100 ≈ 153%.
Now make it realistic
Savings rarely arrive on day one. Suppose year 1 delivers only half of the gross savings while the system stabilises, and the full amount from year 2:
- Year 1 net saving = ₹6,30,000 − ₹6,50,000 + ₹1,50,000 = ₹1,30,000.
- Year 2 onwards = ₹7,60,000.
- Cumulative: ₹1,30,000 after year 1, ₹8,90,000 after year 2, ₹16,50,000 after year 3.
- Payback = 2 + (₹15,00,000 − ₹8,90,000) ÷ ₹7,60,000 ≈ 2.8 years.
A ramp-up of one year moved payback by almost ten months. Use the calculator's growth input to test a cautious and an optimistic case, for example starting at ₹4,00,000 with 20% yearly growth.
A sensitivity table you can build
| Scenario | Net saving per year | Payback (one-time ₹15 lakh, illustrative) |
|---|---|---|
| Optimistic | ₹9,00,000 | about 1.7 years |
| Base case | ₹7,60,000 | about 2.0 years |
| Cautious | ₹5,00,000 | 3.0 years |
| Pessimistic | ₹3,00,000 | 5.0 years |
If the pessimistic case is beyond the period you expect to keep the system, ask whether a smaller scope, a cheaper type of system or a phased rollout would carry less risk. See comparing ERP quotes and the implementation timeline.
How to make the business case credible
- Baseline first. Measure hours, stock, write-offs and debtor days for at least a quarter before the project.
- Name an owner for each saving. The stores head owns stock reduction; the finance head owns reconciliation time.
- Write the saving into a plan. For staff time, say which tasks stop and what the person will do instead.
- Track after go-live. Compare the same measures at 6 and 12 months.
- Do not count grants until sanctioned in writing. See government support for MSME digitisation.
FAQ
What is a "good" payback period for an ERP?
There is no standard. Many owners want payback well within the period they expect to keep the system, with room for the cautious case. Compare against your other uses of the same money.
Should tax savings be included?
They affect the net cost, but they add complexity. For comparing options, a pre-tax payback is usually enough; ask your CA for the after-tax view on large projects.
What if most benefits are not measurable?
Then be honest that the decision rests on judgement: for example, compliance risk, scalability or a customer's requirement. Do not convert vague benefits into rupee figures to make the sum work.
Sources
- Ministry of MSME — MSME schemes and support (do not count until sanctioned)
- Reserve Bank of India — reference rates for the cost of funds
- CBIC GST — late fee and interest rules behind compliance savings
- Institute of Chartered Accountants of India — guidance on cost measurement
