Conversion rate optimisation (CRO) is the systematic process of increasing the percentage of website visitors who complete a desired action — making a purchase, submitting a contact form, signing up to a newsletter, or calling your business. It involves analysing user behaviour, identifying conversion barriers, and testing changes to remove those barriers. CRO is one of the highest-ROI marketing investments available because it generates more revenue from your existing traffic rather than requiring additional spend to acquire more visitors.
The core insight behind CRO is mathematical: if your website converts 2% of visitors and you improve that to 4%, you have doubled your revenue without increasing your marketing budget or your traffic. Most UK businesses focus almost entirely on traffic acquisition (SEO, PPC, social media) while ignoring the conversion rate of the traffic they already have. CRO corrects this imbalance.
How CRO works in practice
- Analysis — understanding current user behaviour through analytics data (Google Analytics 4), heatmaps (Hotjar, Microsoft Clarity), session recordings, and user research
- Hypothesis formation — identifying specific barriers to conversion based on the data: 'Users are dropping off at the pricing page because prices are not displayed'
- A/B or multivariate testing — creating a variation of the page and splitting traffic between the original and the variation to measure which converts better
- Implementation — rolling out the winning variation after statistical significance is confirmed
- Iteration — repeating the process continuously; CRO is a programme, not a project
What CRO typically focuses on
- Homepage and landing pages — the first point of contact for most traffic; clarity, value proposition, and call-to-action are the primary levers
- Product pages (e-commerce) — photography, descriptions, pricing clarity, social proof, and checkout flow
- Lead generation forms — field count, friction, and trust signals immediately around the form
- Checkout (e-commerce) — abandoned cart rate, guest checkout options, payment method availability, and progress indicators
- Pricing pages — clarity, value framing, comparison layout, and social proof placement
- Mobile experience — 60%+ of UK web traffic is mobile; conversion rates on mobile typically lag desktop by 30–50% in under-optimised websites
Average UK website conversion rates by category: e-commerce 1–4% (top performers 5–8%), lead generation landing pages 2–10% (specialist pages with high intent traffic can reach 15–25%), SaaS free trial sign-ups 3–8%, B2B contact forms 1–3%. 'Good' is relative to your traffic quality and category — a complex B2B service with a £50,000 contract value converting at 0.5% may be excellent, while a straightforward consumer e-commerce product at 0.5% would indicate significant optimisation opportunity.
A/B testing is a method used within CRO — not CRO itself. CRO is the overall programme: defining goals, analysing barriers, forming hypotheses, testing solutions, and implementing improvements. A/B testing is the primary experimental tool that CRO uses to determine whether a proposed change improves conversion. CRO programmes also use multivariate testing, user interviews, heatmap analysis, and session recordings — A/B testing is the most important tool but one of many.