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Speed Impact Calculator

How much is slow costing you?

Enter your URL and monthly visitors. We'll estimate how much revenue you're losing to poor Core Web Vitals.

How the speed impact calculator works

1

Measure response

We fetch your URL and measure real server response time, the single biggest factor in perceived page speed. This gives us a baseline for estimating how your page loads under real-world conditions, not synthetic lab tests.

2

Estimate Core Web Vitals

Using response time as a foundation, we model your LCP, INP, and CLS scores. Server-side response time correlates strongly with LCP, a slow TTFB almost guarantees a slow largest paint. We add variance factors for typical render-blocking resources.

3

Calculate revenue impact

For every second your LCP exceeds Google's 2.5s threshold, conversion rates drop roughly 7%. We apply this to your traffic and average order value to estimate monthly revenue loss, a number that makes the business case for performance investment.

The business case for Core Web Vitals

Google confirmed Core Web Vitals as a ranking signal in 2021. Since then, we've watched the gap widen between fast sites and slow ones in competitive search verticals. The ranking impact isn't dramatic on its own, it's a tiebreaker, not a silver bullet. But in markets where ten pages are competing for the same keyword with similar content quality, the page that loads in 1.8 seconds consistently outranks the one loading in 4.5 seconds.

The bigger impact is on conversion. A Deloitte study found that a 0.1-second improvement in mobile load time increased conversion rates by 8% for retail sites and 10% for travel sites. That's not a rounding error. For a site doing $50K per month in revenue, shaving one second off LCP can recover $3,500+ in monthly lost conversions. The ROI on performance optimization is often better than any ad spend increase.

What makes this tricky is that speed degrades invisibly. You launch a fast site, then six months of plugin additions, unoptimized images, and third-party scripts slowly push your LCP from 2 seconds to 4. Nobody notices because the change is gradual. Meanwhile, your bounce rate climbs 1-2% per month and your conversion rate softens. This calculator exists to make that invisible cost visible, so you can decide whether to fix it before your competitors do.

Frequently asked questions

What are Core Web Vitals?
Core Web Vitals are three metrics Google uses to measure real-world user experience. LCP (Largest Contentful Paint) measures how quickly your main content loads, the hero image, the headline, whatever takes up the most screen space. INP (Interaction to Next Paint) measures responsiveness, how fast the page reacts when someone clicks or taps. CLS (Cumulative Layout Shift) measures visual stability, whether elements jump around while the page loads. All three matter for both rankings and user experience.
What's a good LCP score?
Google considers LCP under 2.5 seconds as "good," between 2.5 and 4 seconds as "needs improvement," and above 4 seconds as "poor." In practice, most sites we audit fall in the 3-5 second range. Getting below 2.5 seconds typically requires server-side rendering or static generation, image optimization with modern formats (WebP/AVIF), and eliminating render-blocking CSS and JavaScript. The best-performing sites hit sub-1.5 second LCP.
How accurate is the revenue loss estimate?
The estimate uses a 7% conversion drop per second above the 2.5-second LCP threshold, based on published research from Google and Deloitte. This is a conservative model, some studies show higher drops, particularly on mobile. The actual impact varies by industry (ecommerce sees higher sensitivity than informational sites), device mix, and user intent. Treat the number as a directional indicator, not a precise forecast.
Does Google actually penalize slow sites?
Not as a direct penalty, slow sites don't get demoted. Instead, fast sites get a ranking advantage. The practical effect is the same: if your competitor's page is equally relevant but loads faster, they'll tend to outrank you. The impact is most noticeable in competitive verticals where many sites are targeting the same keywords with similar quality content. Speed becomes the tiebreaker.
What causes high CLS scores?
The most common culprits are images without explicit width and height attributes (the browser doesn't know how much space to reserve), ads or embeds that load after the initial page render and push content down, web fonts that cause visible text reflow (FOIT/FOUT), and dynamically injected content above the fold. Fixing CLS is usually the quickest CWV win, it rarely requires architectural changes, just proper sizing and loading strategies.

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