---
title: "Website Performance Checker: TTFB, Size & Caching"
description: "Audit TTFB, HTML size, compression, cache headers, render-blocking resources, lazy loading, and third-party domains from a server-side page fetch."
canonical_url: "https://webaloha.co/tools/website-performance-checker/"
markdown_url: "https://webaloha.co/tools/website-performance-checker.md"
date_modified: "2026-07-12T00:00:00.000Z"
---
# Website Performance Checker Tool Online

Last updated: Jul 12, 2026

Check any website's performance, TTFB, page size, compression, caching, render-blocking resources, lazy loading, third-party domains, and more. Instant results with actionable fixes.

## How the Performance Checker Works

This tool measures server-side and HTML-level performance without needing a browser engine:

1.  **Enter a URL**, the tool fetches the page and measures the server response time (TTFB) and download time.
2.  **Response analysis**, checks HTTP headers for compression (Gzip/Brotli), caching (Cache-Control), HTTPS, and server identification.
3.  **HTML audit**, scans the markup for external scripts, stylesheets, images, inline assets, render-blocking resources, lazy loading, modern image formats, and preconnect/preload hints.
4.  **Third-party detection**, counts unique third-party domains that require additional DNS lookups and connections.
5.  **Score + recommendations**, you get a performance score, timing metrics, resource breakdown, and specific actionable fixes.

## Why Website Performance Matters

Speed directly impacts your business:

-   **SEO rankings**, Google uses Core Web Vitals as ranking signals. Slow pages lose positions to faster competitors.
-   **Conversion rates**, a 1-second delay in page load can reduce conversions by 7%. Amazon found every 100ms of latency cost 1% in revenue.
-   **Bounce rate**, 53% of mobile users abandon sites that take longer than 3 seconds to load (Google data).
-   **User experience**, fast sites feel more professional and trustworthy. Slow sites frustrate users before they even read your content.
-   **AI search**, AI engines need to crawl and process your pages efficiently. Fast-loading, well-structured pages are more likely to be cited in [AI search results](https://webaloha.co/generative-engine-optimization-geo-complete-guide/).

For complete optimization, also check your [images](https://webaloha.co/tools/image-seo-checker/), [security headers](https://webaloha.co/tools/security-headers-checker/), and [meta tags](https://webaloha.co/tools/meta-tag-checker/). Use the [Font Checker](https://webaloha.co/tools/website-font-checker/) to see if Google Fonts or excessive font weights are adding unnecessary load time. For mobile performance specifically, run the [Mobile-Friendly Checker](https://webaloha.co/tools/mobile-friendly-checker/) to catch viewport and render-blocking issues. Then measure your lab [Core Web Vitals](https://webaloha.co/tools/core-web-vitals-checker/) and break down asset sizes with the [Page Weight Checker](https://webaloha.co/tools/page-weight-checker/).

## Quick Wins for Faster Websites

These fixes deliver the biggest performance gains with the least effort. If you'd rather not tackle them yourself, our [website speed and performance optimization service](https://webaloha.co/website-speed-performance-optimization/) handles all of them for you:

-   **Enable compression**, Gzip or Brotli reduces HTML/CSS/JS transfer size by 60-80%. Most hosting providers support this.
-   **Add defer to scripts**, change `<script src="...">` to `<script src="..." defer>` to eliminate render blocking.
-   **Use a CDN**, serve your site from edge servers near your users. Reduces TTFB dramatically for global audiences.
-   **Lazy load images**, add `loading="lazy"` to below-fold images. Reduces initial page weight significantly.
-   **Use WebP/AVIF**, modern image formats are 25-50% smaller than JPEG/PNG with same quality.
-   **Set Cache-Control**, cache static assets for at least 1 year. Repeat visitors load instantly from browser cache.

## Core Web Vitals Thresholds

Google scores each metric as Good, Needs improvement, or Poor. Aim for "Good" on all three:

| Metric | Good | Needs work | Poor |
| --- | --- | --- | --- |
| **LCP**  
Largest Contentful Paint | ≤ 2.5s | 2.5s – 4.0s | \> 4.0s |
| **INP**  
Interaction to Next Paint | ≤ 200ms | 200ms – 500ms | \> 500ms |
| **CLS**  
Cumulative Layout Shift | ≤ 0.1 | 0.1 – 0.25 | \> 0.25 |

INP replaced First Input Delay (FID) as a Core Web Vital in March 2024. Thresholds apply to the 75th percentile of real-user page loads.

For professional optimization, explore our [SEO services](https://webaloha.co/seo-services/) and [web design services](https://webaloha.co/web-design-services/). To understand the metrics behind your score, read our guide to [Core Web Vitals and how to fix them](https://webaloha.co/core-web-vitals-what-they-are-how-to-fix/).

Next steps

## Performance Checker related tools and articles

Continue with the closest follow-up checks and guides based on this tool's topic, crawl intent, and optimization workflow.

[![Page Weight & Request Count Checker Tool Online](https://webaloha.co/_astro/tool-page-weight.1XeXl0Wn_Z2bivQ5.webp?dpl=dpl_AM1rGg4hZQMeX9Xux5JT1y5ZTCmw)

Page Weight Checker

](https://webaloha.co/tools/page-weight-checker/)[![GZIP & Brotli Compression Test Tool Online](https://webaloha.co/_astro/tool-gzip-test.mf3y10QA_Z1gt4Qz.webp?dpl=dpl_AM1rGg4hZQMeX9Xux5JT1y5ZTCmw)

GZIP / Brotli Test

](https://webaloha.co/tools/gzip-compression-test/)[![Core Web Vitals Checker Tool Online](https://webaloha.co/_astro/tool-core-web-vitals.D8vls4fz_2kM3Ia.webp?dpl=dpl_AM1rGg4hZQMeX9Xux5JT1y5ZTCmw)

Core Web Vitals Checker

](https://webaloha.co/tools/core-web-vitals-checker/)[![Benefits of Static Websites: Speed, Security, and SEO in 2026](https://webaloha.co/_astro/blog-benefits-of-static-websites.BqxhByTc_iSmIb.webp?dpl=dpl_AM1rGg4hZQMeX9Xux5JT1y5ZTCmw)

Benefits of Static Websites: Speed, Security, and SEO in 2026

](https://webaloha.co/benefits-of-static-websites/)[![Website Speed Optimization Pricing: How Much It Costs in 2026?](https://webaloha.co/_astro/blog-website-speed-optimization-cost.D6sZ8rBI_ZV7HHP.webp?dpl=dpl_AM1rGg4hZQMeX9Xux5JT1y5ZTCmw)

Website Speed Optimization Pricing: How Much It Costs in 2026?

](https://webaloha.co/website-speed-optimization-cost/)[![Core Web Vitals: What They Are and How to Fix Them](https://webaloha.co/_astro/blog-core-web-vitals-what-they-are-how-to-fix.DBYqi8WA_1wHB24.webp?dpl=dpl_AM1rGg4hZQMeX9Xux5JT1y5ZTCmw)

Core Web Vitals: What They Are and How to Fix Them

](https://webaloha.co/core-web-vitals-what-they-are-how-to-fix/)

## Performance Checker: FAQ

What does this performance checker measure?

It makes one server-side request and analyzes the returned HTML, response headers, request timing, and markup references to scripts, stylesheets, and images. It does not load the page as a complete browser session.

Is the score a Lighthouse or Core Web Vitals score?

No. The score starts at 100 and subtracts 15 points per detected error and 5 per warning. It is a triage score for this tool's checks, not a Lighthouse score, field data, or a Google ranking metric.

How should I interpret the TTFB result?

It is the elapsed time until this server-side fetch receives the response, including any followed redirects. Network location, cache state, backend load, and bot handling can change it, so repeat tests and compare with real-user or regional monitoring.

Does the HTML size equal the bytes transferred over the network?

Not necessarily. The tool calculates size from the decoded HTML text, while the Content-Encoding header indicates whether transport compression was reported. Use browser network tooling for exact compressed transfer sizes.

How are render-blocking scripts identified?

An external script tag is counted as potentially render blocking when it lacks defer, async, and type="module". This markup heuristic does not model preload behavior, dynamic injection, execution cost, or the browser's full critical rendering path.

Does the resource count include everything the page downloads?

No. It counts image tags and external script and stylesheet references in the initial HTML. It does not fetch those assets or discover resources added by JavaScript, CSS backgrounds, iframes, APIs, fonts, or later interactions.

What should I fix first after a poor result?

Start with errors, then confirm high TTFB, oversized HTML, missing compression, caching, and render-blocking findings in browser traces. Prioritize changes tied to real-user metrics and test again after deployment.

Is the URL or page source retained?

The URL is sent to WebAloha's server for a live request with a 15-second timeout. This endpoint analyzes the response in memory and does not store the submitted URL or result in a database or cache.

Free 48-Hour Website Audit

Not sure what to fix first on your own website? We'll review it and tell you, in plain English. Free & non-obligatory.

[Get My Free Audit 💪](https://webaloha.co/free-website-audit/)

## Need Help Speeding Up Your Website?

We help businesses build fast, optimized websites that rank and convert.

[Explore Speed Optimization 🚀](https://webaloha.co/website-speed-performance-optimization/)