Sales ROI Calculator
A buyer-facing ROI model you build live with the prospect's own numbers, so the payback period you leave behind survives their CFO's second look instead of reading like a vendor-glossy guess.
How to use it
Bring this into the proposal or second meeting and fill Sections 1 and 2 live with the buyer on a shared screen; always lead with the Conservative case and have them initial the Assumptions Log before you leave so the number is theirs to defend internally.
What's inside
- Current-state cost inputs (5 fields: people affected, loaded cost, hours lost, error/rework cost, revenue at risk)
- New-state investment inputs (4 fields: price, implementation cost, ramp cost, internal admin cost)
- Four gain-driver formulas: time saved, error/rework reduction, revenue lift, cost avoidance
- Total Annual Benefit formula
- Net ROI % and Payback Period (months) formulas
- 3-Year Cumulative Value table
- Conservative / Realistic / Aggressive case toggle with a haircut rule for each
- Fully worked numeric example end to end
- Word-for-word script for presenting the number live in the room
- Assumptions Log field for buyer sign-off, so the number survives internal scrutiny after you leave the room
A worksheet you fill in together with the buyer, not a number you hand them.
How to use this in the room
This is a single-formula model built to survive a CFO's second look. Gather the inputs live, on a shared screen or whiteboard, using the buyer's own numbers wherever the field says (ask). If a buyer can't answer a field, use the conservative default noted, never invent a number silently. The credibility of this tool comes from the buyer watching you build it with their own data.
Section 1, Current-State Costs (the cost of staying where they are)
| Field | Value | Source |
|---|---|---|
| A. Number of people affected by this problem | ___ | (ask) |
| B. Fully-loaded cost per person, per year | £___ | (ask; default: base salary × 1.3) |
| C. Hours per week lost to this problem, per person | ___ hrs | (ask) |
| D. Cost of errors/rework per month | £___ | (ask, or rework rate × unit cost) |
| E. Revenue currently at risk or delayed per year | £___ | (ask: late deals, churn, missed SLAs) |
Annual Time Cost = A × B × (C ÷ 40) (C ÷ 40 converts weekly hours lost into a fraction of one full-time role)
Annual Error Cost = D × 12
Section 2, New-State Investment (the cost of the fix)
| Field | Value | Source |
|---|---|---|
| F. Annual price/subscription cost | £___ | (your proposal) |
| G. One-time implementation/setup cost | £___ | (your proposal) |
| H. Ramp cost, lost productivity during rollout (weeks × B ÷ 52 × A × ramp%) | £___ | (estimate; default ramp% = 20%) |
| I. Internal admin cost to manage the solution, per year | £___ | (ask; default: 0.1 FTE) |
Total Year-1 Investment = F + G + H + I Total Year-2+ Investment (annual) = F + I
Section 3, Gain Drivers
| Driver | Formula | Result |
|---|---|---|
| 1. Time saved | Annual Time Cost × expected recovery % (ask, or use 60% conservative) | £___ |
| 2. Error/rework reduction | Annual Error Cost × expected reduction % (ask, or use 50% conservative) | £___ |
| 3. Revenue lift | E × expected recovery % (ask, or use 25% conservative) | £___ |
| 4. Cost avoidance | Any hard cost the buyer stops paying elsewhere (tools retired, contractors cut, penalties avoided) | £___ |
Total Annual Benefit = Driver 1 + Driver 2 + Driver 3 + Driver 4
Section 4: The Three Numbers That Matter
Net ROI % = ((Total Annual Benefit − Total Year-2+ Investment) ÷ Total Year-2+ Investment) × 100
Payback Period (months) = Total Year-1 Investment ÷ (Total Annual Benefit ÷ 12)
3-Year Cumulative Value:
| Year | Investment | Benefit | Net |
|---|---|---|---|
| Year 1 | Total Year-1 Investment | Total Annual Benefit | Benefit − Investment |
| Year 2 | Total Year-2+ Investment | Total Annual Benefit | Benefit − Investment |
| Year 3 | Total Year-2+ Investment | Total Annual Benefit | Benefit − Investment |
| 3-Year Total | Sum | Sum | Cumulative Net |
Section 5: Conservative / Realistic / Aggressive Toggle
Always present three cases, never one number. Buyers trust a range with a visible method more than a single point estimate.
- Conservative, apply a 50% haircut to every recovery %/reduction % in Section 3 before running the formulas. Present this one first.
- Realistic, use the defaults as written above.
- Aggressive, use the buyer's own optimistic estimates if they offer one; otherwise skip it. Never generate this case yourself.
Rule: if the Conservative case still clears a 12-month payback, you have a deal-worthy business case. If it doesn't, don't force it, flag it and revisit scope.
Worked Example
Inputs: A=8 people, B=£65,000, C=6 hrs/week, D=£4,000/month, E=£180,000/year. F=£42,000/year, G=£8,000 one-time, H≈£6,000, I=£6,500/year.
- Annual Time Cost = 8 × £65,000 × (6÷40) = £468,000
- Annual Error Cost = £4,000 × 12 = £48,000
- Total Year-1 Investment = £42,000 + £8,000 + £6,000 + £6,500 = £62,500
- Total Year-2+ Investment = £42,000 + £6,500 = £48,500
Gain Drivers (Realistic case):
- Time saved (60%) = £280,800
- Error reduction (50%) = £24,000
- Revenue lift (25%) = £45,000
- Cost avoidance = £15,000 (a legacy tool being retired)
Total Annual Benefit = £364,800
- Net ROI % = ((£364,800 − £48,500) ÷ £48,500) × 100 = 652%
- Payback Period = £62,500 ÷ (£364,800 ÷ 12) = 2.06 months
- 3-Year Cumulative Net ≈ £364,800×3 − (£62,500 + £48,500×2) = £934,700
Even at the Conservative case (50% haircut on all three recovery rates), payback lands under 4 months, that is the number you lead with.
Live Presentation Script
"Rather than hand you a number, let's build this together with your figures: that way it's your business case, not mine, when you take it upstairs."
[Walk Sections 1 and 2 live, filling in only what the buyer confirms.]
"Based on what you've just told me, here's what staying where you are costs annually, [state Annual Time Cost + Annual Error Cost]. Here's what fixing it costs, [state Total Year-1 Investment]. And here's the return even under a conservative assumption, [state Conservative payback period]. Does that recovery percentage feel realistic to you, or should we make it more conservative still?"
[Let them push the assumptions. Every downward revision they make and still see a sub-6-month payback strengthens the case, because now it's their number.]
Assumptions Log (get this signed/initialed before you leave)
| Assumption | Buyer-confirmed value | Initials |
|---|---|---|
| Recovery %: time | ||
| Recovery %: errors | ||
| Recovery %: revenue | ||
| Ramp period (weeks) | ||
| Case used for the internal business case (Conservative/Realistic) |
This log is what turns your ROI number into their business case: the moment they initial it, they own the defense of it internally, not you.