Gather comparable inputs
Use a consistent period, source definition and currency. Keep estimated pipeline value separate from won revenue.
Cost per lead
CPL = Spend ÷ Leads. If there are no leads, CPL is not defined. CPL measures acquisition cost, not lead quality or downstream revenue.
Conversion
Conversion = Won deals ÷ Leads. Multiply by 100 to express a percentage. If there are no leads, conversion is not defined. Allow for the sales cycle and keep the cohort or reporting window consistent.
Return on investment
ROI = (Revenue - Spend) ÷ Spend × 100. If spend is zero, this formula is not defined. This simple revenue-based calculation excludes other operating costs and is not a profit-margin calculation.
Attribution can involve several interactions. Review missing spend, refunds, currency and the attribution method before interpreting a result. Do not assume the recorded source explains every influence on a sale.