---
title: "Mobile vs desktop Core Web Vitals: INP gap widest, CLS flips"
url: https://seomadman.com/studies/mobile-desktop-cwv-pass-rate-gap
section: studies
published: 2026-08-02T00:00:00.000Z
modified: 2026-08-02T00:00:00.000Z
author: Adam Hafez
topics: ["Technical SEO"]
---

# Mobile vs desktop Core Web Vitals: INP gap widest, CLS flips

## The short answer

HTTP Archive's July 2025 Web Almanac performance chapter breaks Core Web Vitals down by individual metric rather than the all-three pass rate already covered elsewhere. INP shows the widest mobile-desktop split at 77% versus 97%, LCP sits at 62% versus 74%, and CLS reverses the pattern entirely, with mobile passing more often than desktop at 81% against 72%.

## Key takeaways

- The 2025 Web Almanac, using CrUX field data through July 2025, found mobile LCP passes 62% of the time against 74% on desktop, a 12-point gap.
- INP shows the widest split of the three metrics: 77% of mobile websites pass versus 97% of desktop websites, a 20-point gap that narrowed from 23 points in 2024.
- CLS runs the opposite direction of the other two metrics, with 81% of mobile pages passing against 72% on desktop, making mobile the stronger device for that one metric.
- The Web Almanac's chapter does not explain why INP's mobile-desktop gap is so much wider than LCP's, or why CLS reverses the pattern entirely.
- Google's own web.dev guidance on INP cites "considerable variability in the capabilities of devices people use" without attributing the mobile-desktop gap to a single cause.

A widely cited figure says 48% of mobile origins and 56% of desktop origins pass all three Core
Web Vitals as of July 2025. That headline hides more than it shows, because "passes all three"
collapses three very different stories into one number. Broken apart by metric, using the same
July 2025 CrUX data behind that figure, the mobile-desktop gap is not one gap at all: it is wide
for one metric, narrow for another, and reversed for the third.

## INP has the widest gap of the three

Interaction to Next Paint is where mobile and desktop diverge most. The 2025 Web Almanac's
performance chapter puts desktop INP at 97% good, "maintaining the high standard established in
previous years," against 77% good on mobile, up from 74% in 2024. That is a 20-point gap, and the
chapter notes it directly: the mobile-desktop split "has begun to narrow, shrinking from 23
percentage points in 2024 to 20 percentage points in 2025," but a 20-point gap is still the
largest of the three metrics by a wide margin. The chapter does not state a specific cause for the
underlying gap itself, only that it is narrowing. Google's own web.dev guidance on INP is
similarly careful: it flags "considerable variability in the capabilities of devices people use"
as a reason INP thresholds have to accommodate a wide device range, without pinning the
mobile-desktop split on any one factor such as processing power or network conditions.

## LCP splits by a more moderate margin

Largest Contentful Paint passes on 74% of desktop origins against 62% on mobile, a 12-point gap,
roughly half the size of the INP split. The Almanac also reports mobile shows "nearly double the
rate of 'poor' experiences" on LCP compared with desktop, 13% against 7%, so the mobile shortfall
is not just fewer origins clearing the "good" bar; more of them land in the worst tier outright.
As with INP, the chapter documents the size of the gap without stating what drives it.

## CLS is the one metric where mobile wins

Cumulative Layout Shift reverses the direction of the other two: 81% of mobile pages pass CLS
against 72% of desktop pages, a 9-point advantage for mobile. The Almanac notes this is not a
one-off snapshot either, stating that "mobile maintains a higher share of good CLS than desktop
throughout the entire timeframe" when the chapter looks at the trend from 2023 through 2025. The
chapter offers no explanation for why CLS runs opposite to LCP and INP; it only documents that it
does, consistently, across two years of monthly data.

## Why we care

**The all-three figure hides which metric to fix first.** A site told it fails "Core Web Vitals"
on mobile could be failing LCP, INP, or both, and the fix for each is different: LCP work
generally targets render-blocking resources and image weight, INP work targets main-thread
responsiveness to input. Treating "Core Web Vitals" as one problem instead of three risks fixing
the wrong one.

**INP deserves more attention on mobile than the combined figure suggests.** A 20-point gap is the
largest disparity in the dataset, larger than LCP's, and it is the metric most directly tied to
how a page responds to a visitor's taps and clicks rather than how fast it first paints.

**CLS is not a mobile problem at all, by this data.** Sites chasing a lower CLS score on mobile
specifically are optimizing against the metric where mobile already outperforms desktop; the
layout-shift fix, if one is needed, more often belongs on the desktop template.

## Sources

1. [Performance | 2025 | The Web Almanac](https://almanac.httparchive.org/en/2025/performance) - HTTP Archive (primary)
2. [Interaction to Next Paint (INP)](https://web.dev/articles/inp) - web.dev