CPI
CPI is the Acronym for Cost Per Inquiry
A marketing performance metric that measures the average amount spent to generate one qualified lead or expression of interest. An inquiry represents a prospective customer, client, or participant who has taken an action to request information, fill out a form, or otherwise indicate intent to learn more about a product or service. CPI is used across industries—such as education, financial services, healthcare, and B2B marketing—to evaluate the cost-efficiency of lead generation campaigns.
Formula for CPI
Loading formula...For instance, if an organization spends $5,000 on a digital ad campaign that results in 250 inquiries, its CPI would be $20. The lower the CPI, the more efficiently a campaign is converting its marketing investment into potential customer interest.
CPI Purpose and Value
CPI sits at the upper stage of the sales or conversion funnel, serving as an early indicator of how effectively marketing activities attract interested prospects. While not all inquiries result in conversions or sales, tracking CPI helps marketers benchmark channel performance and allocate resources toward the most efficient sources of demand.
CPI is often paired with downstream metrics such as Cost per Lead (CPL), Cost per Acquisition (CPA), or Cost per Sale (CPS) to evaluate performance through the full customer lifecycle. This layered analysis allows organizations to distinguish between inexpensive inquiries with low conversion potential and higher-cost inquiries that yield stronger results.
CPI Applications Across Sectors
In B2B marketing, CPI helps quantify the value of webinars, whitepapers, or gated content campaigns that generate business inquiries. In consumer services like healthcare, finance, or insurance, CPI reflects how efficiently marketing converts ad impressions into customer contacts. In education and training, it is used to evaluate advertising effectiveness in generating prospective student or participant inquiries.
Monitoring CPI allows marketing teams to:
- Identify high-performing channels or campaigns generating quality inquiries at the lowest cost.
- Compare results across digital and offline media, including paid search, display, social, or direct mail.
- Optimize budgets and targeting based on inquiry conversion data.
- Benchmark against industry or peer medians for competitive insights.
A declining CPI often indicates better campaign efficiency or improved targeting, while a rising CPI may signal market saturation, declining ad relevance, or creative fatigue.
