# Website Speed Test: Find What Slows Your Page Down

> Free page speed test: measure TTFB, page weight, compression, render-blocking files and caching, plus real-user Core Web Vitals when Google has data. No signup.

Enter a URL to measure server response, page weight and render blockers, with Core Web Vitals from real Chrome users when Google has them.

- Use it free (no signup): https://yes-seo.com/page-speed-test
- API: `GET https://yes-seo.com/api/v1/page-speed-test?url=https://example.com`
- What it does: Page speed test: server response time (TTFB), download time, HTML size and compression, HTTP version, number and weight of scripts, styles and images, render-blocking resources, caching and modern image formats; Core Web Vitals (LCP, INP, CLS) from Google PageSpeed Insights when available.

Speed is the part of SEO your visitors feel directly. A slow server, a heavy hero image or a stack of render-blocking scripts delays the moment people see your content, and every extra second gives them a reason to go back to the results.

This page speed test measures what happens on the server and in the HTML: time to first byte, download time, HTML size and compression, HTTP version, the number and weight of scripts, styles and images, render-blocking resources, caching headers and image formats. When Google has field data for the URL, it also shows LCP, INP and CLS from PageSpeed Insights.

## How to run a page speed test

1. **Enter the page URL** — Test the pages that matter most, such as top landing pages and product templates, not only the home page.
2. **Read both kinds of data** — Server and page-weight metrics come from our fetch; Core Web Vitals come from real Chrome users when available.
3. **Fix the biggest cost first** — Start with slow TTFB, oversized images and render-blocking files, then re-test the same URL.

## Core Web Vitals thresholds

Google’s [Core Web Vitals](https://web.dev/articles/vitals) measure loading, responsiveness and visual stability for real Chrome users, assessed at the 75th percentile of page loads:

| Metric | Good | Needs improvement | Poor |
| --- | --- | --- | --- |
| LCP (Largest Contentful Paint) | ≤ 2.5 s | 2.5–4 s | > 4 s |
| INP (Interaction to Next Paint) | ≤ 200 ms | 200–500 ms | > 500 ms |
| CLS (Cumulative Layout Shift) | ≤ 0.1 | 0.1–0.25 | > 0.25 |

INP replaced First Input Delay in March 2024. Field data comes from the Chrome UX Report over a rolling 28-day window, so improvements take weeks to show, and low-traffic pages may have no data at all. Our [Core Web Vitals guide](https://yes-seo.com/blog/core-web-vitals-guide) covers each metric in depth.

## Reading the server-side numbers

- **[TTFB](https://yes-seo.com/glossary/ttfb):** time until the first byte of HTML arrives. web.dev suggests 0.8 s or less as a rough target. Everything else, LCP included, waits for it; page caching and a CDN are the usual fixes.
- **Compression:** HTML, CSS and JavaScript should be served with Brotli or gzip.
- **HTTP version:** HTTP/2 or HTTP/3 lets the browser fetch many files over one connection.
- **Requests and weight:** every script and stylesheet costs download and processing time; images are usually the heaviest bytes.
- **[Render-blocking resources](https://yes-seo.com/glossary/render-blocking):** stylesheets and synchronous scripts in the head that must load before anything is painted.
- **Caching:** static files without long cache lifetimes are downloaded again on every visit.
- **Image formats:** WebP and AVIF are typically much smaller than JPEG or PNG at similar quality.

## Fixes that move LCP, INP and CLS

Load the main image early and never lazy-load it; give every image dimensions so it can’t shift the layout:

```

```

The `defer` attribute keeps scripts from blocking the first paint. For INP, shorten long main-thread tasks: remove unused third-party tags, split heavy event handlers and yield back to the browser between chunks of work. For CLS, reserve space for ads, embeds and cookie banners with fixed dimensions or `aspect-ratio`.

## Caching static files

Files whose names change with each release, such as `app.3f9a1c.js`, can be cached for a year. On Nginx:

```
location ~* \.(css|js|woff2|avif|webp|jpg|png|svg)$ {
    add_header Cache-Control "public, max-age=31536000, immutable";
}
```

On Apache, the same value goes in a `<FilesMatch>` block with `Header set Cache-Control`. Only do this for fingerprinted file names: a plain `style.css` cached for a year means returning visitors keep the old design after you change it. Verify the result with the [HTTP header checker](https://yes-seo.com/http-header-checker).

## Tips for a faster page

- Fix templates, not single URLs: speeding up the product template speeds up every product page at once.
- Resize images before uploading; a 4,000-pixel photo shown in a 600-pixel slot wastes most of its bytes.
- Review third-party tags every few months; chat widgets, heatmaps and forgotten pixels often cost more than your own code.
- Self-host critical fonts in WOFF2 and preload only the one or two files used above the fold.
- Re-test after each change rather than after ten, so you know which fix actually helped.

## Limits to keep in mind

Our test fetches the page from our server and doesn’t run JavaScript or render the page, so it measures server response, file weights and HTML structure rather than lab paint timings. Core Web Vitals appear only when PageSpeed Insights has real-user data for the page. For a full lab run in a real browser, use Lighthouse in Chrome DevTools or [PageSpeed Insights](https://pagespeed.web.dev/), and check mobile layout issues with the [mobile-friendly test](https://yes-seo.com/mobile-friendly-test).


## Frequently asked questions

### What is a good page speed?

Aim for Good on all three Core Web Vitals: LCP within 2.5 seconds, INP within 200 milliseconds and CLS of 0.1 or less, for at least 75% of visits. On the server side, a TTFB under about 0.8 seconds is a sensible target.

### Why are Core Web Vitals missing for my page?

They come from real Chrome users, and Google only publishes them once a page or site has enough traffic. New and low-traffic pages often have none, so rely on lab measurements from Lighthouse in the meantime.

### Why do my results differ from PageSpeed Insights or GTmetrix?

Each tool tests from a different location, device profile and connection speed, and lab results vary from run to run. Compare trends within one tool, and treat field data as the closest view of what users experience.

### Does page speed affect Google rankings?

Core Web Vitals are part of the page experience signals Google uses, but relevance and content quality matter far more. Speed rarely makes a weak page rank, yet a slow page can still lose visitors and sales.

### What replaced First Input Delay?

Interaction to Next Paint (INP) replaced FID as a Core Web Vital in March 2024. It reflects how quickly the page responds to clicks, taps and key presses across the whole visit, with 200 milliseconds or less counted as good.

### How can I reduce TTFB?

Cache full pages where you can, put a CDN in front of the site, speed up slow database queries and move off underpowered hosting. On WordPress, a page-caching plugin or host-level cache usually brings the biggest gain.