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Complete Guide

Everything you need to know about using SpeedCheck Pro and understanding your performance metrics

Pair this handbook with Calendarcosmos — Calendarcosmos helps round out your optimization workflow with complementary tooling.

Table of Contents

Getting Started

How to Test Your Website

  1. Enter your website URL in the input field on the home page (e.g., https://example.com)
  2. Choose your device type:
    • Mobile - Simulates a mid-tier smartphone with 4G connection
    • Desktop - Simulates a desktop browser with broadband connection
  3. Click "Test Now" to start the performance analysis
  4. Wait 30-60 seconds while our tool runs comprehensive Lighthouse tests
  5. Review your results including performance score, Core Web Vitals, and recommendations

Understanding Your Results

Your performance report contains several key sections:

  • Performance Score (0-100) - Overall rating based on multiple metrics
  • Core Web Vitals - Key metrics Google uses for search ranking
  • Additional Metrics - Supplementary performance measurements
  • Resource Breakdown - Analysis of JavaScript, CSS, images, and other assets
  • Recommendations - Prioritized optimization opportunities with impact levels

Sharing Your Results

Each test generates a unique shareable link that you can:

  • Copy and share with your team via the "Copy Link" button
  • Share directly on Twitter, LinkedIn, or Facebook using the social share buttons
  • Bookmark for future reference
  • Include in reports or presentations

Note: Report links are stored for 30 days. Your test history is also saved locally in your browser.

Understanding Core Web Vitals

Core Web Vitals are a set of real-world metrics that Google uses to measure user experience and search rankings. These metrics directly impact your SEO performance.

LCP - Largest Contentful Paint

Measures how long it takes for the largest visible element to load in the viewport. This is typically a hero image, heading, or large block of text.

Good
< 2.5 seconds
Needs Improvement
2.5 - 4.0 seconds
Poor
> 4.0 seconds

How to improve: Optimize images, remove render-blocking resources, use a CDN, improve server response times.

INP - Interaction to Next Paint

Measures page responsiveness by tracking the time from when a user interacts with your page (clicks, taps, keyboard) to when the browser shows a visual response.

Good
< 200 ms
Needs Improvement
200 - 500 ms
Poor
> 500 ms

How to improve: Reduce JavaScript execution time, break up long tasks, use web workers, optimize event handlers.

CLS - Cumulative Layout Shift

Measures visual stability by tracking unexpected layout shifts during page load. Ever clicked a button only to have content shift and you click the wrong thing? That's poor CLS.

Good
< 0.1
Needs Improvement
0.1 - 0.25
Poor
> 0.25

How to improve: Set size attributes on images/videos, reserve space for ads, avoid inserting content above existing content

Performance Score Explained

The Performance Score is a weighted average of multiple metrics measured by Google Lighthouse. It ranges from 0 to 100, with higher scores indicating better performance.

90-100
Excellent
Fast performance
50-89
Needs Work
Room for improvement
0-49
Poor
Needs urgent attention
Target
95+
Optimal performance

Metric Weightings

  • Largest Contentful Paint (LCP) - 25%
  • Total Blocking Time (TBT) - 30%
  • First Contentful Paint (FCP) - 10%
  • Speed Index - 10%
  • Time to Interactive (TTI) - 10%
  • Cumulative Layout Shift (CLS) - 15%

Detailed Metrics Guide

FCP - First Contentful Paint

Time until the first text or image appears. Good: < 1.8s. This measures when users first see any content, providing early feedback that the page is loading.

TTFB - Time to First Byte

Time until the browser receives the first byte of the response from the server. Good: < 800ms. This indicates server response speed and network latency.

Speed Index

Measures how quickly content is visually displayed during page load. Good: < 3.4s. Lower scores indicate faster visual progress.

Total Blocking Time (TBT)

Total time the main thread is blocked, preventing user input. Good: < 200ms. High TBT indicates heavy JavaScript execution that delays interactivity.

Acting on Recommendations

Your performance report includes prioritized recommendations based on potential impact. Focus on high-impact items first for the best return on optimization effort.

Priority Levels

High

Critical issues with significant performance impact. Address these first.

Medium

Moderate impact. Implement after addressing high-priority items.

Low

Minor improvements. Nice to have but not urgent.

Common Optimization Categories

  • Images: Compress, resize, use modern formats (WebP, AVIF), implement lazy loading
  • JavaScript: Minify, remove unused code, defer non-critical scripts, use code splitting
  • CSS: Minify, remove unused styles, inline critical CSS, defer non-critical styles
  • Fonts: Use system fonts or optimize web fonts with font-display: swap
  • Caching: Implement proper cache headers, use service workers for offline support
  • Server: Enable compression (gzip/brotli), use HTTP/2 or HTTP/3, reduce redirects

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