A mobile-friendly checker that measures the page on a phone-sized screen
Google retired its Mobile-Friendly Test in December 2023, but the question it answered still matters: will this page work on a phone? This mobile-friendly checker fetches a page, reads its HTML and stylesheets, and lays it out in a 390 px wide sandboxed preview — the width of a typical modern phone — to measure what can be measured without running its scripts.
It checks the viewport meta tag, finds elements that make people scroll sideways, measures how much text is smaller than 12 px, spots tap targets that are too small and too close together, and lists fixed widths and tiny font sizes in the CSS, wide tables and embeds, and obsolete plugins such as Flash. You can watch the result in the phone preview as you read the list.
How to check if a page is mobile friendly
- Enter the Page address — or choose Paste HTML for a page that isn’t online yet.
- Press Check mobile-friendliness. The page and up to six of its stylesheets are fetched, then rendered at 390 px with scripts off.
- Read the score and the prioritised list; the top items usually explain most of what is wrong.
- Look at the Phone preview and the measured tables: elements wider than the screen, crowded tap targets, fixed CSS widths and small font sizes.
- Fix the CSS or HTML and check again; for a full audit with scripts running, follow the PageSpeed Insights link.
Mobile-Friendly Checker features
Measured, not guessed
The page is actually laid out at 390 px, so sideways scrolling, text size and tap-target size come from real element boxes, not from rules of thumb.
Phones without a viewport, emulated
Pages with no mobile viewport are laid out about 980 px wide and shrunk to fit, as phones do — which is why their text becomes unreadable.
Stylesheets read properly
CSS is parsed by your browser, with media queries evaluated for a 390 × 844 px screen, so desktop-only rules and phone overrides are understood.
Tap targets by WCAG 2.2
Targets under 24 × 24 px are flagged only when they are also crowded, and links inside sentences are exempt, following success criterion 2.5.8.
Safe preview
The fetched HTML is shown in a sandboxed frame with scripts, event handlers, embedded frames and plugins removed, and links in it don’t navigate.
What happened to Google’s Mobile-Friendly Test?
Google switched off the Mobile-Friendly Test tool, its API and the Mobile Usability report in Search Console in December 2023. It said mobile usability still matters — Google indexes the mobile version of pages — but that better tools now exist, and it recommends Lighthouse. This page fills the quick “does it work on a phone?” gap; PageSpeed Insights gives the full Lighthouse report with scripts running.
The thresholds used
| Check | Passes when | Based on |
|---|---|---|
| Viewport | width=device-width, zoom not blocked | Responsive design practice; WCAG 1.4.4 Resize text |
| Sideways scrolling | Nothing is wider than 390 px (measured) | WCAG 1.4.10 Reflow (320 CSS px) |
| Text size | At least 90% of characters are 12 px or larger | Lighthouse fails a page when over 40% is smaller |
| Tap targets | 24 × 24 px or enough space around them | WCAG 2.2 success criterion 2.5.8 |
| Plugins | No object, embed or Flash | Flash end of life, 31 December 2020 |
Worked example
A shop page has a correct viewport but adds user-scalable=no, a promo banner fixed at width: 1200px, a table with width="800", a 560 px video embed and a Flash object. At 390 px the page measures 1,200 px wide, so the checker lists the banner, the table, the embed placeholder, a 500 px paragraph and the object as the elements sticking out. Its .legal text at 10 px and an icon menu at 11 px make 44 of 150 characters smaller than 12 px — a warning — and three 16 × 16 px icon links side by side are flagged as crowded tap targets. A .wrap { width: 960px } rule is not listed, because a max-width: 600px media query resets it on phones.
Limits worth knowing
- Scripts don’t run, so menus, carousels and content a script draws may look different, and layout changes made by JavaScript are not measured.
- Only the first six stylesheets (and their first-level @import files) are read; the preview loads pictures and fonts directly from the site.
- Some sites block automated visitors; paste the HTML instead. To see the live page at different widths, try the Webpage Screenshot tool, and check the head of the page with the Meta Tag Analyzer.
Mobile-Friendly Checker FAQ
Is there still a Google Mobile-Friendly Test?
No. Google retired it, together with its API and the Search Console Mobile Usability report, in December 2023 and recommends Lighthouse. This mobile-friendly checker covers the common problems those tools reported.
How do I check if my website is mobile friendly?
Enter a page address here and press Check mobile-friendliness. You get a score, a list of problems in priority order and a 390 px preview; fix the high-priority items first.
Why does the preview look different from my phone?
Scripts are switched off for safety, so anything built or changed by JavaScript is missing, and fonts or pictures the site blocks for other origins may not load. The real page can differ.
What causes horizontal scrolling on mobile?
Usually something with a fixed width wider than the screen: an image without max-width, a wide table, a video embed with width="560", or a CSS width in pixels. The measured table names the outermost elements that stick out.
What font size is good for mobile?
Body text of 16 px is the usual baseline. Lighthouse flags pages where more than 40% of the text is under 12 px; this tool warns from 10%.
Does mobile-friendliness affect Google rankings?
Google indexes the mobile version of pages, and page experience is part of its guidance, but no single mobile check is a ranking formula. Fix what hurts phone users and the rest follows.