Your website might look great on the surface, but if it loads slowly, glitches, or feels unresponsive, visitors won’t stick around. A website performance test is the best way to find out how your site really performs and what’s slowing it down.
In this guide, we’ll explain what a website performance test is, why it matters, and how you can run one even if you’re not a developer.
What Is a Website Performance Test?
A website performance test analyzes how fast and efficiently your website loads and responds.
It checks things like:
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Page speed
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Image optimisation
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Server response time
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File sizes
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Browser caching
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Mobile performance
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Code quality
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Hosting performance
If anything is too slow, too large, or poorly configured, these tools will show you, usually with a score and recommendations.
Why Website Performance Matters
Slow websites hurt your business. Here’s why:
1. Users Leave After 3 Seconds
Studies show that 53% of visitors leave a site that takes more than 3 seconds to load.
If your site is slow, you’re losing potential customers before they even see your content.
2. Google Rankings Drop
Speed is a known Google ranking factor.
A slow site = lower visibility = fewer leads.
3. Conversions Decrease
Every extra second of load time reduces conversions by up to 20%.
If your website is meant to bring in enquiries or sales, performance is critical.
4. It Affects Your Brand
A sluggish, buggy site makes your business feel outdated and unprofessional.
Fast websites feel trustworthy.
The Best Tools to Run a Website Performance Test
You don’t need coding knowledge, just type in your URL.
1. Google PageSpeed Insights
Shows mobile & desktop scores plus detailed suggestions.
Great for beginners.
2. GTmetrix
Gives speed scores, waterfall charts, and loading breakdowns.
Excellent for diagnosing issues.
3. Pingdom Tools
Simple performance testing with clear grades and timings.
4. WebPageTest.org
More advanced testing for developers (TTFB, filmstrip, real-browser data).
What to Look for in Your Results
When you run a test, focus on these key metrics:
Page Load Time
Ideally under 2-3 seconds.
Largest Contentful Paint (LCP)
Measures how quickly your main content loads.
Under 2.5 seconds is ideal.
Total Blocking Time (TBT)
Shows if scripts delay loading.
Cumulative Layout Shift (CLS)
Measures layout stability (no jumping around).
Image Size
Large, uncompressed images slow everything down.
Server Response Time (TTFB)
If this is slow, your hosting may be the issue.
How to Improve Your Website Performance
If your website performance test shows poor results, here’s how to fix it:
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Compress and resize images
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Minify CSS, JS, and HTML
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Enable browser caching
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Use a Content Delivery Network (CDN)
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Reduce plugins
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Remove unused code
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Optimise your WordPress theme
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Upgrade your hosting
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Enable lazy loading for images
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Reduce redirects
Even small improvements can make a huge difference.
Need Help Improving Your Website Performance?
At SwiftSites, we optimise websites to load fast, score highly on performance tests, and convert more visitors.
If your website feels slow, or your test results are confusing, we can fix it.
Just reach out and we’ll run a full performance audit for you.
