Email marketing impact WordPress sites
Performance impact by email_marketing provider.
1
At a glance the headline numbers for Email marketing impact
Performance impact by email_marketing provider.
4
Providers ranked
After min-sites filter
3,152
Sites in sample
Combined across all items
0.02
Best CLS (p75)
Klaviyo
The State of Web Vitals · October 2026 · WordPress sites (63,295) · phone field datacorewebvitals.io/state-of-cwv
2
The ranking sorted by CLS at p75, fastest first
| # | Provider | CLS p75 | Passing | Sites | |
|---|---|---|---|---|---|
| 1 | Klaviyo | 0.02 | 92.3% | 271 | |
| 2 | Mailchimp | 0.02 | 88.8% | 1,568 | |
| 3 | HubSpot | 0.03 | 85.2% | 1,071 | |
| 4 | ActiveCampaign | 0.04 | 84.8% | 242 |
The State of Web Vitals · October 2026 · WordPress sites (63,295) · phone field datacorewebvitals.io/state-of-cwv
3
Passing CLS per provider which group passes the CLS most often
ProviderSitesPassing CLSp75
Klaviyo 0.4% 271 0.02
Mailchimp 2.5% 1,568 0.02
HubSpot 1.7% 1,071 0.03
ActiveCampaign 0.4% 242 0.04
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good CLS (0.1 at p75) · one value per site
92% of Klaviyo sites pass CLS. ActiveCampaign trails 7 points behind. computed
The State of Web Vitals · October 2026 · WordPress sites (63,295) · phone field datacorewebvitals.io/state-of-cwv
4
All five vitals at once the whole category without toggling - cell is the pass rate, small number the p75
LCP
INP
CLS
FCP
TTFB
Mailchimp 2.5%
613.0s
96121ms
890.02
492.6s
202.1s
HubSpot 1.7%
603.0s
94136ms
850.03
492.6s
281.9s
Klaviyo 0.4%
652.9s
97141ms
920.02
472.6s
172.1s
ActiveCampaign 0.4%
613.0s
94142ms
850.04
472.6s
301.9s
60%95%+ passing Cell: pass rate, small number = p75 · faded rows: under 100 sites
One row per provider, one column per vital - the cell is the share of sites passing, the small number the p75. No toggling needed to see where the category actually differs.
Klaviyo leads on CLS: 92% of its sites pass. ActiveCampaign trails at 85%. computed
The State of Web Vitals · October 2026 · WordPress sites (63,295) · phone field datacorewebvitals.io/state-of-cwv
Related signals Font services (4) → Session recording (11) → CMS (17) → Search (6) → 203,892 crawled sites with Chrome field data, representing millions of real page loads · How we measured
203,892 crawled sites with Chrome field data, representing millions of real page loads. How we measured.