This page brings together the page speed statistics worth citing: how many sites pass Google's Core Web Vitals, how load time relates to bounce and abandonment, what controlled studies found about speed and conversions, and what Google itself says about speed as a ranking signal.
Each number links to the page where it was published. Several of the most quoted figures come from Google research in 2016 to 2018, when average mobile pages were far slower than today; those rows show their year so you can judge them. Newer field data comes from the HTTP Archive's Web Almanac, which measures millions of real sites using Chrome user data.
Core Web Vitals pass rates
Core Web Vitals are Google's three field metrics for loading (LCP), responsiveness (INP) and visual stability (CLS). The Web Almanac reports the share of sites with good scores, measured from real Chrome users.
| Statistic | Source | Year |
|---|---|---|
| 48% of mobile sites pass all three Core Web Vitals, up from 44% in 2024. | HTTP Archive, Web Almanac 2025: Performance | 2025 |
| 56% of desktop sites pass all three Core Web Vitals, up from 55% in 2024. | HTTP Archive, Web Almanac 2025: Performance | 2025 |
| 62% of mobile sites and 74% of desktop sites have a good Largest Contentful Paint (2.5 seconds or less). | HTTP Archive, Web Almanac 2025: Performance | 2025 |
| 77% of mobile sites and 97% of desktop sites have a good Interaction to Next Paint (200 ms or less). | HTTP Archive, Web Almanac 2025: Performance | 2025 |
| 81% of mobile sites and 72% of desktop sites have a good Cumulative Layout Shift (0.1 or less). | HTTP Archive, Web Almanac 2025: Performance | 2025 |
| Only 44% of mobile sites and 55% of desktop sites have a good Time to First Byte. | HTTP Archive, Web Almanac 2025: Performance | 2025 |
| Median Total Blocking Time is 1,916 ms on mobile, against 92 ms on desktop. | HTTP Archive, Web Almanac 2025: Performance | 2025 |
The Almanac's data is from July 2025. Mobile scores lag desktop mainly on loading: slower networks and processors hit LCP and TTFB hardest. Layout shift is the one metric where mobile does better.
Page weight
Heavier pages take longer to load, especially on mobile networks.
| Statistic | Source | Year |
|---|---|---|
| The median mobile home page weighs 2,559 KB, and the median desktop home page 2,862 KB. | HTTP Archive, Web Almanac 2025: Page weight | 2025 |
| The median home page makes 75 requests on mobile and 80 on desktop. | HTTP Archive, Web Almanac 2025: Page weight | 2025 |
| Images account for 911 KB of the median mobile home page. | HTTP Archive, Web Almanac 2025: Page weight | 2025 |
| In Google's 2018 analysis of 11 million mobile ad landing pages, 79% were over 1 MB and 23% were over 4 MB. | Google, New industry benchmarks for mobile page speed | 2018 |
| In that analysis, as page elements rose from 400 to 6,000, the probability of conversion dropped 95%. | Google, New industry benchmarks for mobile page speed | 2018 |
Load time, bounce and abandonment
These are the most quoted speed numbers on the web. All come from Google's mobile research of 2016 to 2018, built on large samples of real sites.
| Statistic | Source | Year |
|---|---|---|
| 53% of mobile visits are likely to be abandoned if pages take longer than 3 seconds to load. | Google, The need for mobile speed | 2016 |
| As mobile page load time goes from 1 second to 10 seconds, the probability of a bounce increases 123%. | Google, New industry benchmarks for mobile page speed | 2018 |
| The average mobile site took 19 seconds to load over a 3G connection in Google's 2016 sample of 10,000+ mobile domains. | Google, The need for mobile speed | 2016 |
| Sites loading in 5 seconds had 70% longer average sessions and 25% higher ad viewability than sites loading in 19 seconds. | Google, The need for mobile speed | 2016 |
| Google's model projected that publishers whose mobile sites load in 5 seconds earn up to 2x more mobile ad revenue than those loading in 19 seconds. | Google, The need for mobile speed | 2016 |
| Bounced sessions had DOM ready times 55% slower than sessions that did not bounce. | Google, Why marketers should care about mobile page speed | 2016 |
| 54% of people say their frustration grows as a brand's mobile load time increases. | Google, Milliseconds earn millions | 2018 survey |
| The BBC found it lost an additional 10% of users for every extra second its site took to load. | Google web.dev, Why speed matters | Undated case |
The 2018 benchmarks article updated a study Google first published in 2017. It was based on a neural network that Google says predicted bounces with 90% accuracy, so read the 123% as a modelled probability.
Speed and conversions
Conversion studies split into two kinds: large correlational datasets, and controlled A/B tests where only speed changed. The A/B tests are the stronger evidence.
| Statistic | Source | Year |
|---|---|---|
| A 0.1 second improvement in mobile site speed increased retail conversions by 8.4% and travel conversions by 10.1%. | Deloitte Digital and 55 for Google, Milliseconds make millions | 2019 data, published 2020 |
| In the same study, retail consumers spent 9.2% more after the speed gain. | Deloitte Digital and 55 for Google, Milliseconds make millions | 2020 |
| In Vodafone's A/B test, a 31% better LCP produced 8% more sales. | Google web.dev, Vodafone case study | 2021 |
| Rakuten 24's Core Web Vitals A/B test raised revenue per visitor 53.37% and conversion rate 33.13%. | Google web.dev, Rakuten 24 case study | Updated 2022 |
| E-commerce pages loading in 1 second converted at 3.05%, against 1.12% at 3 seconds. | Portent, site speed and conversion rate research | 2022 |
| A B2B site loading in 1 second converts at 3x the rate of one loading in 5 seconds. | Portent, site speed and conversion rate research | 2022 |
| A 100-millisecond delay in load time can hurt conversion rates by 7%. | Akamai, State of Online Retail Performance | 2017 |
| In retail, a 1-second delay in mobile load time can affect conversion rates by up to 20%. | Google, Milliseconds earn millions, citing SOASTA 2017 | 2017 |
The Deloitte study covered 37 brand sites and over 30 million sessions, and the gains appeared only when every page in the journey got faster. Portent's dataset was just over 100 million page views across 20 sites over 30 days. Akamai's figure comes from roughly 10 billion visits to retail sites and is correlational.
What Google says about speed and rankings
Google's own documentation is the only direct source on how speed affects rankings.
| Statistic | Source | Year |
|---|---|---|
| Good Core Web Vitals thresholds: LCP within 2.5 seconds, INP under 200 ms, CLS under 0.1. | Google Search Central, Core Web Vitals | Current |
| Google states that "Core Web Vitals are used by our ranking systems." | Google Search Central, Page experience | Current |
| Google's Speed Update made page speed a ranking factor for mobile searches from July 2018, affecting only the slowest pages and a small percentage of queries. | Google Search Central Blog, Using page speed in mobile search ranking | 2018 |
| Interaction to Next Paint replaced First Input Delay as a Core Web Vital on March 12, 2024. | Google web.dev, INP becomes a Core Web Vital | 2024 |
Google also says there is "no single signal" for page experience. Where many pages answer a query well, a good page experience can help; where one page is clearly the most relevant, Search may still show it with weaker scores. The bigger payoff from speed usually shows up in conversions on the visits you already earn.
What these numbers mean for site owners
- Fix LCP first. It is the Core Web Vital most sites fail on mobile. Compress and correctly size the hero image, serve it in a modern format, and cut server response time.
- Test on a phone, on a real connection. Desktop scores flatter you. Check field data in PageSpeed Insights or Search Console's Core Web Vitals report.
- Count your page elements. Every script, font and tracking tag adds weight. Google's data ties element count closely to lower conversion probability.
- Measure the business result. The strongest evidence comes from A/B tests. If you change speed, compare conversions before and after on the same pages.
- Keep speed in proportion. Relevant content still wins rankings. Our SEO statistics and mobile search statistics put speed in context, and for clinics, medical website speed walks through the fixes. The technical SEO audit checklist covers the rest of the site.
FAQ
Is page speed a Google ranking factor?
Yes. Google confirms Core Web Vitals are used by its ranking systems, and the 2018 Speed Update applied page speed to mobile rankings. Google also says relevance comes first: a slow page with the best answer can still rank, and the speed signal mainly affects the slowest pages.
What is a good page load time?
Google's target for Largest Contentful Paint is 2.5 seconds or less at the 75th percentile of real visits. Google's 2016 research found 53% of mobile visits were likely abandoned after 3 seconds, so under 3 seconds for the main content is a sensible goal.
Is it true that a 1-second delay cuts conversions by 7%?
The commonly quoted version is a mix-up. Akamai's 2017 retail report found that a 100-millisecond delay can hurt conversion rates by 7%. For a full second, Google cites SOASTA data showing a 1-second mobile delay can affect retail conversion rates by up to 20%.
How many websites pass Core Web Vitals?
In July 2025 Chrome field data, 48% of mobile sites and 56% of desktop sites passed all three Core Web Vitals, according to the HTTP Archive's Web Almanac 2025.
Does improving speed increase sales?
Controlled tests say it can. Vodafone's A/B test found a 31% better LCP produced 8% more sales, and Rakuten 24 saw conversion rate rise 33% after optimizing for Core Web Vitals. Results depend on how slow the site was to begin with.
Sources and method
We chose figures from field datasets (HTTP Archive and Chrome UX Report), Google's published research and documentation, and studies with a stated sample or a controlled test design. Older Google figures are included because they remain the standard citations, with their year shown. Vendor studies (Akamai, Portent) are labelled with their sample. Every figure and link was checked on 2026-10-08.
