Measuring marketing ROI for UK small businesses (2026)

Marketing ROI is part maths, part politics. Here's how UK small businesses can measure it honestly in 2026 — without pretending the data is cleaner than it is.

Pick one attribution model and stick with it

Last non-direct click in GA4 is the most defensible default for small businesses. Don't switch models mid-year — it makes period-on-period comparison meaningless.

LTV/CAC over CPL

Cost per lead is a vanity metric. Lifetime value divided by customer acquisition cost is the number that decides whether marketing is profitable. Aim for at least 3:1 over 18 months.

Payback period

How long until acquired customers cover their own CAC? Under 6 months is healthy for most B2C. Under 12 months for B2B. Longer than that and cashflow becomes the constraint.

What to communicate to the board

Three numbers: blended CAC, LTV/CAC, and revenue attributable to marketing-sourced contacts. Everything else is supporting detail.

Frequently asked questions

Pick one attribution model and stick with it?

Last non-direct click in GA4 is the most defensible default for small businesses. Don't switch models mid-year — it makes period-on-period comparison meaningless.

LTV/CAC over CPL?

Cost per lead is a vanity metric. Lifetime value divided by customer acquisition cost is the number that decides whether marketing is profitable. Aim for at least 3:1 over 18 months.

Payback period?

How long until acquired customers cover their own CAC? Under 6 months is healthy for most B2C. Under 12 months for B2B. Longer than that and cashflow becomes the constraint.

What to communicate to the board?

Three numbers: blended CAC, LTV/CAC, and revenue attributable to marketing-sourced contacts. Everything else is supporting detail.