Calculate your cost per lead across channels and find how many leads you need to hit your revenue target. Compare CPL, lead quality and close rate to find your most cost-efficient acquisition channel.
Monthly channel data:
| Channel | Spend | Leads | CPL | Cost per Customer |
|---|
Cost Per Lead is one of the most tracked marketing metrics — and one of the most misused. A low CPL from a channel that converts poorly at the close stage can be more expensive than a higher CPL with better lead quality. The metric that matters is Cost Per Customer (CPL ÷ close rate), not CPL alone. Understanding both, and how they interact with deal size, determines your true acquisition efficiency.
A social campaign generates 80 leads at £15 CPL (£1,200 total). A paid search campaign generates 20 leads at £45 CPL (£900 total). If social leads close at 5% and paid search leads at 20%: Social cost per customer = £15 ÷ 5% = £300. Paid search cost per customer = £45 ÷ 20% = £225. Paid search is the more efficient channel despite higher CPL. Always calculate CPL alongside your channel-specific close rate.
B2B SaaS: £40–£200 per lead (MQL). Professional services: £30–£150. E-commerce product page enquiry: £5–£30. Webinar/event registration: £20–£100. LinkedIn Lead Gen Forms: £50–£200. Warm referral: £0–£30. Referral leads close at 3–5× the rate of cold leads, making them typically the most cost-efficient overall despite not always appearing so on CPL alone.
Not all leads are created equal. Implement lead scoring to track which channels produce higher-quality leads: ICP fit (company size, industry, job title), engagement (email opens, page visits, content downloads), and CRM stage progression velocity. Channels with lower CPL but lower quality scores may have higher cost per qualified lead and cost per customer once quality is factored in.
CPL benchmarks vary enormously by industry and channel. B2B SaaS: £50-200 for an MQL (marketing qualified lead). Professional services: £30-150. E-commerce enquiry: £5-30. The more relevant benchmark is maximum allowable CPL = Deal Value × Close Rate. If deal value is £2,000 and close rate 15%, max CPL (at 3:1 LTV:CAC) = £2,000 × 15% / 3 = £100. Above this, the channel is too expensive.
Leads needed = Revenue target / (Deal value × Close rate). For £30,000 monthly target, £1,200 average deal, 15% close rate: deals needed = 25. Leads needed = 25 / 15% = 167 leads/month. At £45 CPL, monthly budget needed = £7,515. This reverse calculation from revenue target through to required lead volume and budget is the foundation of marketing planning.
Main approaches: (1) Improve ad targeting to reach higher-intent audiences — qualified traffic converts at lower volume but higher rate; (2) Test landing pages — a 1% to 2% improvement halves CPL on the same spend; (3) Optimise ad creative and messaging for click-through rate; (4) Leverage owned channels (email, organic SEO) which have lower marginal CPL; (5) Referral and partnership programmes typically produce the lowest CPL of any channel.