If your speed scores in Jetpack Boost seem to change every time you refresh them, don’t worry — that’s expected. This guide explains why these variations happen, what’s considered normal, and how to get the most accurate results from Boost.
Quick Summary
- Small score fluctuations are normal and expected.
- Mobile scores are usually lower than desktop scores.
- PageSpeed Insights may show different results due to averaging and other test conditions.
- Run a few tests and look for trends, not exact numbers.
Why does the score change every time I refresh it?
Speed tests are affected by many small variables — even when your site hasn’t changed. Jetpack Boost uses Lighthouse, an open-source tool by Google, to test your site — just like Google PageSpeed Insights. Each test is a snapshot in time, so some variation is expected. Some things that can cause scores to fluctuate:
- Temporary network or server slowdowns.
- Different test server locations.
- Whether the page was cached at the time of the test.
- Background activity on your site during the test.
We’re working on improving this by running multiple tests and averaging them — but for now, it’s normal to see different scores from one refresh to the next.
Why is the mobile score lower than the desktop score?
Jetpack Boost uses Lighthouse to simulate how your site performs on a slower mobile device. That means:
- Lower bandwidth.
- Slower processor.
- Stricter performance requirements.
Most sites score lower on mobile — that’s expected. You don’t need a perfect mobile score to have a fast, usable site.
Tip: If most of your traffic comes from mobile visitors, focus your improvements there first. You can track changes over time using Performance History (available on paid plan).
Why is my Jetpack Boost score different from PageSpeed Insights?
Both Jetpack Boost and PageSpeed Insights use Lighthouse, but results may still differ.
Here’s why:
- PageSpeed Insights runs multiple Lighthouse tests and averages the result.
- Boost runs a single Lighthouse test per refresh.
- Google may use different testing infrastructure and servers.
The important thing is not the exact number — it’s the overall trend. If your score is improving and users say your site feels faster, you’re on the right track.
Get more consistent test results
If your scores feel all over the place, try this the following:
- Test a few times and look for a trend, not a single number.
- Clear your cache (site and CDN) before testing.
- Use a private/incognito browser window.
- Avoid testing during updates or high site traffic.
When should I contact support?
You don’t need to worry about small score changes, but reach out if:
- Your score drops significantly and doesn’t bounce back.
- The refresh button fails or throws an error.
Still need help?
Please contact support. We’re happy to advise.
