LCP on Mobile

  • 30 July 2021
  • 5 replies


Hi Everyone, 

Is anyone else experiencing bad LCP values on mobile? 

The website is really fast on mobile and destkop, but according to GTmetrix, uptrends, ligthouse etc. the LCP on mobile is around 8 - 10 Seconds.

I am running (semi) dedicated websites. It keeps coming back on a lot of sites. 
For example:

5 replies

Userlevel 4
Badge +2

Unrelated but I was looking at your site and there is a style bug with your menu that you’d probably would like to take a look at. Screenshot.

Additionally, I think you might want to unload WordPress’ block library from your pages, since you’re now using Elementor. Loading this unused CSS makes you LCP time score worse.

Now coming to the actual subject, I think this is due to your header image. It is 328kb which is huge considering its size. A good hero image size would be max 200kb. I think the transparency is what’s making this one particularly heavy. Instead of giving your image a shape using transparency, consider CSS masking with an SVG shape, or even using different breakpoints so you load a smaller background image on mobile (although I have never used this trick, it might be worth a short).



Thank you for your reply. 
I will have a look at the menu, thanks! 

Still about the LCP. I have changed header image to a smaller one with 57kb size.
It did improve some, but still 7 seconds loading time. 

I can’t understand why.
When I look at the original trace the LCP is just under a second, but the calculated one is 7s .

Userlevel 4
Badge +2

Honestly, I’m not sure what the original trace might mean here. Perhaps it would be wise to drop a line to the Google forums? I think GTMetrix would tell you when the LCP happens. Do you have a link to a recent test?


Well the calculated results are the results that you see in the page speed score. 
When you look in devtools lighthouse (chrome) for the pagespeed score you can click on original trace and see the original (not calculated) LCP. 

I will have a look at this mate. 
Thanks for your help

Userlevel 7
Badge +4

@Jos Salfischberger did you find your answer here? If so, please consider clicking “✔ Best answer” to help out others. If you found it elsewhere, please share it here so we can mark your answer as the best one.