Core Web Vitals pass rate before and after moving to Next.js, by origin platform
| From | Pass before | Pass after | Change (points) | Good INP before | Good INP after | Sites |
|---|---|---|---|---|---|---|
| Gatsby | 22.6% | 39.4% | +16.8 | 46.1% | 51.4% | 134 |
| Nuxt | 17.1% | 20.5% | +3.4 | 35.0% | 40.8% | 143 |
| WordPress | 33.2% | 32.2% | -1.0 | 67.6% | 53.7% | 511 |
| Drupal | 35.8% | 28.5% | -7.3 | 65.5% | 50.0% | 110 |
| WooCommerce | 29.0% | 21.5% | -7.5 | 70.6% | 41.0% | 123 |
| Webflow | 44.7% | 30.4% | -14.3 | 73.7% | 45.5% | 79 |
| Magento | 39.5% | 18.5% | -21.0 | 72.4% | 42.5% | 81 |
| Shopify | 41.5% | 13.3% | -28.2 | 56.3% | 34.1% | 45 |
| All eight origins | 31.4% | 28.5% | -2.9 | 61.9% | 48.4% | 1,226 |
Source: PageSpeed Matters, Oct 2026. Origins with 30+ movers only. Months 2 to 4 before vs months 1 to 3 after each switch.
Summary
Next.js is one of the most common targets for a site rebuild, and speed is often part of the pitch. We checked what happened to real-user Core Web Vitals on sites that moved to it.
On average, not much, and slightly worse. Across 1,226 top 1M sites that moved to Next.js, the Core Web Vitals pass rate went from 31.4% to 28.5%. The average hides big differences: moves from Gatsby improved, moves from WordPress were flat, and moves from commerce platforms fell hard.
What we measured
We used HTTP Archive monthly crawls of the top 1M sites from Sept 2024 to Sept 2026 to find platform switches. A switch counts when a site was detected on one platform for 3+ months and then on Next.js for 3+ months. For each site we compared the share of months that passed Core Web Vitals in months 2 to 4 before the switch with months 1 to 3 after it, using Chrome UX Report field data, then averaged across sites.
The main group of 1,226 sites covers the eight origin platforms with 30+ movers each and leaves out smaller origins. The popularity split uses all 1,282 Next.js arrivals, which went from 31.0% to 28.1% overall. Platform is detected from the framework only, and many moves come with a redesign, so these results describe what happened after the switch, not what Next.js alone did.
Pass rates dipped slightly overall
Before the switch, the 1,226 sites passed Core Web Vitals 31.4% of the time. After it, they passed 28.5% of the time, a 2.9 point dip.
Slightly more sites got worse than better. 23.3% of the 1,226 (286) lost pass rate after the move and 19.7% (241) gained. The rest were unchanged. Most sites saw no change in pass rate, and among those that did, slightly more lost ground than gained it.
28.5%
Core Web Vitals pass rate of 1,226 sites in months 1 to 3 after moving to Next.js, down from 31.4% before.
Results depend on where the site came from
Where a site came from shapes the result. Moves from Gatsby improved, from 22.6% to 39.4% passing (134 sites). Nuxt to Next.js rose slightly, from 17.1% to 20.5% (143 sites). Moves from WordPress were flat, at 33.2% before and 32.2% after (511 sites).
Everything else fell. Drupal moves went from 35.8% to 28.5% (110 sites) and Webflow moves from 44.7% to 30.4% (79 sites). Commerce origins fared worst: Shopify to Next.js fell from 41.5% to 13.3% (45 sites) and Magento to Next.js from 39.5% to 18.5% (81).
The pattern likely reflects the starting point. Gatsby and Nuxt sites were already JavaScript framework sites with low pass rates, so a rebuild had room to help. Webflow, Shopify and Magento sites started from higher pass rates, so they had more to lose.
Loading improved, responsiveness fell
Moves to Next.js trade responsiveness for loading speed. Across the 1,226 sites, the share of months with good LCP rose from 53.3% to 61.2%, but good INP fell from 61.9% to 48.4%. Good CLS barely moved, from 69.4% to 68.6%.
The INP drop shows up for most origins. WordPress sites went from 67.6% good INP to 53.7%, WooCommerce from 70.6% to 41.0% and Webflow from 73.7% to 45.5%. Only Gatsby and Nuxt, which were already JavaScript framework sites, improved on INP. Hydration and client-side JavaScript likely play a part, since they add work on the main thread when a visitor first interacts.
Popular sites lost more
Next.js arrivals ranked in the top 100K went from 27.4% passing to 21.0% (233 sites). The 1,049 ranked lower went from 31.8% to 29.7%.
Popular sites started lower and fell further. They may carry more tracking and third-party code, though this data does not show that directly.
What this means for your site
A move to Next.js is not a speed fix on its own. If you are planning one:
- Know your starting point. Sites that moved from Webflow, Shopify or Magento started with higher pass rates and lost the most; moves from WordPress were flat.
- Set an INP target before you build. Loading tended to improve after the move; responsiveness tended to get worse.
- Render on the server where you can, and keep client-side JavaScript to the parts of the page that need it.
- Audit third-party scripts before launch, especially on a high-traffic site.
- Measure field data for a few months on both sides of launch, so you can see what the move actually did.
Sources
- HTTP Archive monthly crawls of the top 1M sites, Sept 2024 to Sept 2026, with Chrome UX Report field data, analyzed October 2026
- web.dev, Interaction to Next Paint (INP): https://web.dev/articles/inp
Embed this research
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<iframe id="psm-next-js-migration-speed" src="https://www.pagespeedmatters.com/embed/data-studies/next-js-migration-speed" width="100%" height="600" style="width:100%;border:1px solid #E2E3E1;border-radius:12px" loading="lazy" title="Next.js Migration Speed: 31.4% to 28.5% Pass CWV - PageSpeed Matters"></iframe>
<script>window.addEventListener("message",function(e){if(e&&e.data&&e.data.psmEmbed==="next-js-migration-speed"&&e.data.height){var f=document.getElementById("psm-next-js-migration-speed");if(f){f.style.height=e.data.height+"px";}}});</script>
<p style="font:14px/1.5 system-ui,sans-serif">Source: <a href="https://www.pagespeedmatters.com/resources/data-studies/next-js-migration-speed">Next.js Migration Speed: 31.4% to 28.5% Pass CWV - PageSpeed Matters</a></p>
Frequently asked questions
Does moving to Next.js improve Core Web Vitals?
On average, no. Across 1,226 sites that moved to Next.js, the pass rate went from 31.4% to 28.5%. Moves from Gatsby improved (22.6% to 39.4%), while moves from Shopify, Magento and Webflow fell.
Why does INP get worse after a move to Next.js?
Our data shows the drop but not its cause. Across 1,226 sites, good INP fell from 61.9% to 48.4% while good LCP rose from 53.3% to 61.2%; client-side JavaScript and hydration are a likely factor.
Is Next.js faster than WordPress?
Not in this data. 511 sites that moved from WordPress to Next.js went from a 33.2% pass rate to 32.2%, and good INP fell from 67.6% to 53.7%.
A rebuild planned around field data and an INP budget can keep the loading gains of a new framework without losing responsiveness. Need help with this? See our website migration services.