h4 vs understrap

h4 is used by more websites in our catalog: 666 use h4 and 103 use understrap.

understrap sites have the higher median Ahrefs Domain Rating (h4: 8, understrap: 31).

Between 2026-06 and 2026-07, h4 went from 0.07% to 0.08% of all tracked sites, while understrap went from 0.01% to 0.01%. h4 is gaining ground faster in our index.

No. A site runs a single WordPress theme, so h4 and understrap are mutually exclusive.

Adoption is counted from Site Stats Database's own crawl; Domain Rating comes from Ahrefs and traffic from DataForSEO. Figures reflect the sites we track and refresh at least monthly.