A concise reference of common formulas PPC marketers use — ready to paste into dashboards or documentation.
Formulas use: Cost, Clicks, Impr (impressions), Conv (conversions), Revenue, Orders, Customers, and Period.
| Metric (abbr.) | Formula | Notes / Variations |
|---|---|---|
| CPC | CPC = Cost / Clicks |
Average cost paid for each click. |
| CPM | CPM = Cost / (Impr / 1000) |
Cost per 1,000 impressions (display/video bidding). |
| CTR | CTR = Clicks / Impr |
Often shown as a percentage: multiply result by 100. |
| CVR (or CR) | CVR = Conv / Clicks |
Conversion rate from clicks to conversions (can also be Conv / Sessions). |
| CPA / Cost per Acquisition | CPA = Cost / Conv |
Also called Cost per Conversion; goal metric for performance campaigns. |
| CPL | CPL = Cost / Leads |
Used when objective is lead-gen rather than immediate sale. |
| ROAS | ROAS = Revenue / Cost |
Often shown as a ratio (e.g., 4 = $4 revenue per $1 spent) or percent. |
| ROI | ROI = (Revenue - Cost) / Cost |
Shows profit relative to spend; multiply by 100 for percent. |
| AOV | AOV = Revenue / Orders |
Important for ecommerce to link ad spend to average order value. |
| ARPU | ARPU = Revenue / Users |
Average revenue per user (period-specific). |
| CAC | CAC = (Total Sales + Marketing Cost) / New Customers |
Include spend and human costs for accuracy. |
| CLV / LTV | CLV = AOV × Purchase Frequency × Avg Customer Lifespan |
Variations exist (discounted cash flows for advanced models). |
| CAC : LTV Ratio | LTV : CAC = CLV / CAC |
Common target: LTV : CAC ≥ 3 (depends on business model). |
| Impression Share (IS) | IS = Impr / Eligible Impr |
Google Ads reports; shows share of auctions you won. |
| Search Lost IS (budget) | Lost_IS_budget = % Impr lost due to budget |
Platform-provided; indicates missed opportunity from limited budget. |
| Quality Score (proxy metrics) | QS ≈ f(Ad Relevance, CTR, Landing Page Exp) |
No public exact formula; monitor CTR & relevance as proxies. |
| View-Through Rate (VTR) | VTR = View-Through Conversions / Impr |
Used for display/video conversions without a click. |
| Revenue per Click (RPC) | RPC = Revenue / Clicks |
Useful when optimizing bids by expected revenue per click. |
| Revenue per Impression (RPI) | RPI = Revenue / Impr |
Small value numbers; multiply by 1000 for revenue per thousand impressions. |
| Conversion Value / Cost | Value/Cost = ConvValue / Cost |
Similar to ROAS when ConvValue = Revenue. |
| Profit | Profit = Revenue - Cost - Variable Costs |
Use when calculating true profitability beyond ad costs. |
| Break-even ROAS | Break-even ROAS = 1 / GrossMargin% |
Minimum ROAS to cover product cost (e.g., GM% = 40% → BREakeven ROAS = 2.5). |
| Attribution-adjusted CPA | Adj_CPA = Cost × (Attributed_Conv_Share / Conv) |
Adjust CPA when using multi-touch attribution; implementation varies. |
$2.50$2010 (1000%)