What is PLS by device
PLS by device breaks down your Perceived Load Speed (PLS) by different device types such as Mobile, Desktop, and Tablet. It helps you understand how fast your website feels across various hardware experiences and user contexts.
Since PLS measures how fast the full page appears loaded to the user (not just the largest element like LCP), it’s especially sensitive to device differences in rendering capability, processing power, and network behavior.
This lens helps pinpoint where users feel delays — whether it's on mobile phones with weaker CPUs or desktops burdened by heavy scripts.
Healthy PLS by device sample
Should you worry
A healthy PLS by device lens shows all device types in the green zone. While it’s natural for some variation to exist — for example, slightly slower perceived speeds on older mobile phones — green across the board indicates a consistently fast visual experience for all users.
If any device type falls into yellow or red, that’s a signal to investigate further. The issue might lie in how the page visually renders on that device, not just how fast the server responds.
Unhealthy PLS by device sample
An unhealthy PLS by device view often shows mobile or desktop users disproportionately experiencing slow visual loading. This can result from factors like underpowered devices, excessive use of third-party scripts, or layout shifts that delay perceived completeness.
When users perceive slowness, they're less likely to engage — especially if they're on the go or multitasking.
Resolving unhealthy PLS by device
Go-to action plan to resolve an unhealthy PLS by device:
Ask Uxi to analyze your PLS by device and suggest improvements.
Use Filters to isolate the slowest device category, then explore additional PLS lenses to identify which pages or elements are dragging it down.
Simulate LCP of the suspected lens to see if fixing it will resolve the PLS by device. If yes, this is where the resolution focus should be.
Use an automated optimization tool like Navigation AI to improve your PLS by device.
Once you’ve improved PLS, set an alert to be the first to know if it starts worsening again.
Try it yourself
Discover how your website performs with real user data.