A CFO who does not trust ad spend is not being difficult. They are asking a fair question: does the PPC budget generate more revenue than it costs. PPC ROI answers that question directly, and calculating it correctly takes one formula and three inputs most marketing teams already have in Google Ads and their CRM.
This guide walks through how to calculate PPC ROI, the two mistakes that quietly distort the number, and how to build a model a marketing manager can bring into a budget review before the CFO asks for it.
The PPC ROI formula
PPC return on investment compares revenue generated from paid campaigns against what was spent to generate it. The formula is fixed and does not need a specialist tool to run:
PPC ROI (%) = ((Revenue from PPC - Ad Spend) / Ad Spend) x 100Revenue from PPC is the closed revenue you can attribute to paid clicks, not clicks or leads on their own. Ad spend is the total media cost for the period, including any management fee if one applies. Everything else in this guide is about getting those two inputs right before the formula ever runs.
Worked example
| Input | Value |
|---|---|
| Ad spend (30 days) | AED 40,000 |
| Closed revenue attributed to PPC | AED 90,000 |
| Net gain | AED 50,000 |
| PPC ROI | 125% |
A 125% ROI means every dirham spent returned AED 1.25 in profit on top of the original spend, not AED 1.25 in total revenue. That distinction is usually the first thing a CFO checks, so state it plainly rather than let the percentage speak for itself.
Where the inputs usually go wrong
The formula is simple. The two inputs that feed it are where most PPC return on investment figures fall apart before they reach a stakeholder.
- Attribution model mismatch: last-click attribution credits only the final ad interaction before a sale, which understates PPC’s role in longer buying journeys where a paid click starts the research and a branded search or direct visit closes it. A blended or data-driven attribution model in Google Ads gives a fairer picture for any account with a sales cycle longer than a single session.
- Sales cycle lag on B2B leads: a lead generated by a campaign this month may not close for six to twelve weeks. Measuring ROI on the same 30-day window as ad spend understates performance for any B2B account with a real sales cycle, since the revenue side of the formula has not caught up yet.
- Mixing platforms without separating spend: combined Google Ads and Meta reporting hides which channel drives the revenue side of the equation, which matters when a founder asks which platform to cut first in a tighter budget.
Google’s own guidance on attribution models explains how each model assigns credit differently, and it is worth reading before picking one for a PPC ROI report: see Google Ads Help on attribution models.
Building the model before a budget review
A marketing manager does not need PPC-specific software to build this. A spreadsheet with three tabs, built in this order, holds up under CFO-level scrutiny.
- Pull raw spend and conversion data from Google Ads for the period under review, broken out by campaign, not blended into one account total.
- Match conversions to closed revenue in the CRM, using the attribution window that fits the actual sales cycle rather than the platform’s default.
- Run the ROI formula per campaign, not just at account level, so the report shows which specific campaigns are earning their spend and which are not.
Running the formula per campaign rather than at account level is what turns this from a defensive exercise into a genuinely useful budget tool: it tells a founder exactly where to add spend, not just whether PPC in general is worth keeping.
Proving it to a stakeholder who does not trust ad spend
A CFO who is skeptical of ad spend is not persuaded by a single percentage on a slide. They want to see the two numbers behind it, spend and closed revenue, side by side, before they accept the ratio drawn from them.
Present the spend-to-revenue relationship first, then the resulting ROI figure as the conclusion it is, not the headline. Pair it with the attribution model used and the date range, so the number cannot be dismissed as a rounding trick or a cherry-picked window. A CFO who can see how the figure was built is far more likely to trust the figure itself.
For accounts where the numbers genuinely do not add up, that is the point to review campaign structure and targeting rather than the reporting method. Dominate Online’s PPC management service audits campaign structure, attribution setup and budget allocation together, so the ROI a stakeholder sees next quarter reflects a properly built campaign, not just a better spreadsheet.
Related reading: Dominate Online’s guide to PPC strategies and best practices covers the campaign-level decisions that feed directly into this ROI model.
Frequently asked questions
Why does my PPC ROI look worse than my Google Ads conversion value?
Google Ads conversion value often uses last-click attribution and can include soft conversions such as newsletter sign-ups. PPC ROI, built from closed CRM revenue, only counts deals that closed, so it is normal for the two figures to diverge, particularly on longer B2B sales cycles.
Should I calculate PPC ROI including or excluding the agency management fee?
Include it. A CFO evaluating whether PPC is worth funding wants the true cost of running the channel, not just the media spend, so the management fee belongs in the ad spend side of the formula.
My PPC ROI is negative this month. Does that mean I should pause the campaign?
Not automatically. Check the sales cycle lag first: a negative monthly figure on a B2B account with a six to eight week sales cycle often means revenue has not caught up with recent spend yet, not that the campaign has stopped working.
How often should I recalculate PPC ROI for a stakeholder report?
Monthly for most accounts, but align the reporting window to the actual sales cycle length rather than the calendar month if the two differ by more than a few weeks, otherwise the figure understates performance every single period.