Free CLS Calculator — Measure Cumulative Layout Shift
Check your Cumulative Layout Shift score and identify exactly which elements are causing unexpected layout shifts on your pages.
Free — no account required for a single check. Sign up for continuous monitoring →
What the CLS Calculator checks
CLS score (Good/Needs Improvement/Poor)
Shift sources identified
Elements causing layout instability
Size of largest shift
Fix recommendations
How it works
Runs a Lighthouse session with layout instability detection enabled to capture and score all layout shifts during page load.
Monitor continuously — not just once
This free tool runs a one-off check. AuditJet monitors your site on a schedule — alerting you when scores change, before performance regressions affect your rankings and revenue.
CLS Calculator — FAQ
Is the CLS Calculator free?
Yes — CLS Calculator is completely free to use. No account required for a single-URL check.
How does the CLS Calculator work?
Runs a Lighthouse session with layout instability detection enabled to capture and score all layout shifts during page load.
What does the CLS Calculator check?
CLS score (Good/Needs Improvement/Poor). Shift sources identified. Elements causing layout instability. Size of largest shift. Fix recommendations.
How is this different from Google PageSpeed Insights?
Google PageSpeed Insights is a one-off manual tool. AuditJet adds continuous monitoring, regression alerting, and revenue impact on top of the same performance analysis — so you're notified when scores change, not just when you remember to check.