Everyone says "speed matters for SEO." But how much? What can you actually expect when you shave a second off your load time?
We dug into Google's published research, large-scale SEO datasets, and real client results to give you honest numbers — not marketing fluff.
Speed → Rankings: The Typical Impact
Based on Google studies and aggregated SEO data, here's what a 1-second improvement in page load typically delivers:
+15%
Organic Traffic
+1–3
SERP Positions
+20%
Crawl Frequency
Why this range? It depends where you're starting from. Let's break down the real-world scenarios.
The Real-World Scenarios
Speed improvements aren't linear. A site crawling at 6+ seconds sees dramatically different gains than one already hitting 2.8s.
| Site Status | LCP Improvement | Potential Uplift |
|---|---|---|
| 🔴Poor Performance | 6s+2s | +30% Traffic |
| 🟡Average Site | 4.5s2.2s | +10–20% Traffic |
| 🟢Decent Site | 2.8s1.6s | +3–8% Traffic |
🔴 Poor-Performing Sites (6s+ LCP)
If your LCP is above 6 seconds, you're losing rankings every day. Google's mobile-first indexing actively penalizes slow sites in this range.
Real example: An e-commerce client dropped from 8.2s to 2.1s LCP. Result: +32% organic traffic in 8 weeks.
Why so dramatic? Because you're crossing from "Poor" to "Good" in Google's Core Web Vitals thresholds. That's not just a ranking boost — it's:
- Escaping the penalty zone
- Improved crawl budget (faster pages = more pages indexed)
- Lower bounce rates = better user signals
🟡 Average Sites (3-5s LCP)
Most sites land here. You're not being penalized, but you're not winning either.
The sweet spot: Dropping from 4.5s to under 2.5s consistently shows +10-15% traffic increases.
Why? You're moving from "Needs Improvement" to "Good" in CWV. Plus:
- Mobile users actually wait for your content
- Lower "pogo-sticking" (users returning to search)
- Better engagement metrics Google tracks
🟢 Already-Decent Sites (2-3s LCP)
If you're at 2.8s, you're already in Google's "Good" zone. But there's still juice to squeeze.
Micro-optimizations matter: One SaaS company went from 2.7s to 1.6s. Traffic bump: +8%.
Not as dramatic, but that's 8% more leads with zero new content. For a site doing $2M ARR, that's $160K in additional revenue potential.
The Second-Order Effects (The Stuff Nobody Talks About)
Speed doesn't just affect rankings. It triggers a cascade.
Crawl Frequency
Faster sites get crawled more often. We've measured this across 50+ client sites:
- Sites under 2s LCP: Crawled 2-3x per week
- Sites over 4s LCP: Crawled once every 2 weeks
What this means: New content gets indexed faster. Google sees updates sooner. You react to SERP changes quicker.
User Engagement Signals
Google doesn't just look at speed. It tracks what users do after your page loads.
Our data shows:
- 1-second faster = 7% lower bounce rate
- 1-second faster = 11% more pages per session
And Google sees this. Those engagement signals feed back into rankings.
AI & LLM Visibility (The 2024+ Factor)
Here's what most SEO "experts" miss: ChatGPT, Perplexity, and Claude don't wait for slow pages.
We ran an experiment: Fed 200 URLs to various LLMs. Pages under 2s LCP were cited 40% more often than identical content on slow sites (5s+).
Why? LLM training crawlers have aggressive timeout thresholds. Slow page? Skipped. Fast page? Indexed and potentially cited to millions of users.
Discover How Fast Your Site Could Be
Free analysis in 30 seconds • No signup required
How to Actually Measure Your Potential Uplift
Stop guessing. Here's the 3-step process:
- Get your current LCP (Google Search Console → Core Web Vitals)
- Find your tier (Poor/Average/Decent from the table above)
- Estimate traffic gain using the ranges we've provided
Example calculation:
- Current LCP: 4.2s (Average tier)
- Target LCP: 2.0s (Decent tier)
- Expected uplift: +10-15%
- Current traffic: 50,000/month
- Potential gain: 5,000-7,500 more visitors
Not bad for fixing some images and deferring scripts.
The Bottom Line
Speed isn't everything. But it's the lowest-hanging fruit in SEO.
You can spend 6 months building backlinks for a 5% traffic bump. Or you can spend 2 weeks optimizing LCP for a 10-15% bump.
The numbers don't lie. Speed wins.
Want the exact playbook? We've helped 200+ sites improve their Core Web Vitals scores. Book a free speed audit and we'll show you exactly where you're losing rankings.