www.nhs.uk speed test — 20 Oct 2026

What these numbers mean

• The first byte took 595 ms. Everything else waits for that number, so the server is where to start: caching, a slow query, or an overloaded host.
• The page transfers 345.8 KB over 14 request(s), which is lean. Javascript files are 77% of it, so defer what is not needed for the first screen, and drop tags nobody uses.
• The HTML itself arrives gzip-compressed.
• It runs over HTTP/3, so the assets share a connection instead of opening one each.
• 78% of the weight comes from other hosts (analytics, fonts, embeds), which also means their slow day becomes your slow day.
• The largest element painted at 2.25 s, inside the 2.5 s Google calls good.
• Layout shift is 0.241 (good is under 0.1): something without a reserved size is loading late - an image, an ad, or a font swap.
• The main thread was blocked for 139 ms in total, which is not enough to feel.

Fix first: Server response time (TTFB) - Cut server think time: page cache, query indexes, fewer synchronous calls to third parties inside the request. Connection setup is distance, so a nearer region or a CDN edge helps instead.

Read on one shared server, not a visitor's phone: use it to compare pages against each other, not as a promise about every connection. We fix what these tests find.