⚡ Lazy Loading Threshold Calculator
Optimize viewport loading · IntersectionObserver vs native lazy
📐 Viewport height (px)
📱 Auto-detect
📄 Total page height (px)
🖼️ Number of images / iframes
📍 RootMargin (px before viewport, negative = delay)
earlier
later
⟳ Recalculate
resources below fold:
0
⚡ native loading="lazy"
vs
🧩 IntersectionObserver + rootMargin
0% deferred
0% deferred
0
Immediate load
0
Deferred
0%
Weight savings
0%
TTI improvement
0 KB
Bounce bandwidth saved
0 KB
Native lazy (est.)
⬆️ above fold
⬇️ below fold
🟦 load trigger (rootMargin)
⬜ deferred