LCP Calculator

LCP Calculator — calculate lcp for tech projects. Formula, specs, and practical notes.

A page speed impact calculator estimates the revenue effect of website load time improvements. Research consistently shows that slower page loads reduce conversion rates, increase bounce rates, and lower search engine rankings — all of which reduce revenue. Google's Core Web Vitals (LCP, FID/INP, CLS) are now direct ranking signals, making page speed both a conversion and an SEO issue. The financial case for page speed investment is typically the most compelling argument for engineering and management prioritisation. Profit Margin Calculator and Markup Calculator provide the baseline metrics needed to calculate page speed revenue impact.

Enter current monthly sessions and conversion rate.
Enter current average page load time (use Google PageSpeed Insights or Core Web Vitals for LCP).
Enter target load time after optimisation.
Apply the load time to conversion rate relationship: typically each 1-second improvement in load time increases mobile conversion rate by 2–7%.
Calculate revenue uplift: sessions × (improved CVR − current CVR) × AOV.

Page speed revenue impact formula

CVR improvement estimate = Load time reduction (seconds) × CVR impact per second (2–7%)

Revenue uplift = Monthly sessions × CVR improvement × AOV

Worked example: 80,000 monthly sessions. Current load time 4.2 seconds. Target 2.5 seconds. Reduction 1.7 seconds. Estimated CVR improvement at 3% per second: 5.1%. Current CVR 2.5%. Improved CVR 2.6275%. Revenue uplift = 80,000 × 0.001275 × 65 = 6,630/month additional revenue from speed improvement alone.

Page speed benchmarks

Google Core Web Vitals thresholds

Google Core Web Vitals targets (2024): Largest Contentful Paint (LCP) — Good: under 2.5s; Needs improvement: 2.5–4s; Poor: over 4s. Interaction to Next Paint (INP) — Good: under 200ms; Poor: over 500ms. Cumulative Layout Shift (CLS) — Good: under 0.1; Poor: over 0.25. Sites meeting all three thresholds gain a ranking boost in Google Search. Mobile load time is the critical measurement — mobile typically loads 2–3× slower than desktop and has the highest share of traffic for consumer e-commerce.

Technology tips and best practices

Images are the largest load time contributor on most pages — compress and convert images to WebP format; implement lazy loading for off-screen images.
Eliminate render-blocking resources — JavaScript and CSS that block page rendering should be deferred or inlined for critical above-the-fold content.
Use a CDN (Content Delivery Network) for static assets — serving assets from servers physically close to users reduces latency significantly for global audiences.

See formula and results sections for key figures and benchmarks.

Common mistakes to avoid

See tips section for common pitfalls to avoid.

Page speed optimisation is a technical practice with no specific legal requirements beyond general website accessibility obligations. In some jurisdictions, accessibility standards (WCAG) may indirectly relate to performance for users with assistive technologies. CDN and hosting provider agreements govern data residency and availability SLAs. This calculator is for planning purposes only.