font-display strategy
The font-display strategy on declared fonts: swap, block, optional, fallback, auto.
At a glance the headline numbers for font-display strategy
The font-display strategy on declared fonts: swap, block, optional, fallback, auto.
49.5% of fonts use font-display swap. 9.4% still hide their text while loading.
The font-display strategy mix who uses what, and how fast each group loads
font-display strategy. On the fleet: 49.5% swap, 40.0% auto, 9.4% block. 57.7% of sites use at least one swap.
Lowest-share bucket: LCP 1.4s. Highest-share bucket: LCP 1.6s. r = +0.24.
Passing LCP per bucket every category and count level at once - color is the pass rate
Each row is a category, each column its own count bucket (few on the left, many on the right); the cell is the share of those sites passing LCP.
Auto swings the hardest: 87% of sites pass LCP with few, 59% with many. computed
Few vs many - does quantity cost LCP? the pass rate with few vs many of each category
Per category: the pass rate among pages with FEW of it (hollow ring) against pages with MANY (solid dot), worst trend first. Thin buckets are excluded from the endpoints.
More Auto costs the most: the LCP pass rate falls from 87% with few to 59% with many. computed
Why this matters for the Core Web Vitals, and where to start fixing it
font-display decides what text does while the web font downloads. block hides it: invisible text, and a direct LCP delay when the LCP element is text. swap shows the fallback font immediately and switches when the web font lands, and that switch reflows the page (CLS) when the two fonts have different metrics. optional shows the fallback and only uses the web font if it arrives fast, which is the safest setting for the vitals.
The CLS half of swap is fixable without giving up the font: tune the fallback with size-adjust and the override descriptors so the swap barely moves anything.
How does this affect the Core Web Vitals?
Of the 5 categories, Block separates passing sites from failing sites the most. Where Block is rare: 86% pass the LCP. Where it is common: 76%.
Chrome field data from 94,910 sites, representing millions of real page loads. How we measured.