Calculate first contentful paint from its network and rendering components.
First contentful paint marks when the user first sees anything. Render-blocking resources are usually the largest controllable component, and eliminating them moves FCP earlier directly. FCP is what users perceive as the page starting to load, which is why it drives bounce rate even though LCP drives ranking.
First Contentful Paint
FCP = TTFB + critical CSS time + render-blocking resource time
FCP = TTFB + critical CSS time + render-blocking resource time First contentful paint marks when the user first sees anything. Render-blocking resources are usually the largest controllable component, and eliminating them moves FCP earlier directly.
FCP is what users perceive as the page starting to load, which is why it drives bounce rate even though LCP drives ranking.
This calculator takes 5 inputs: DNS lookup, TCP and TLS handshake, Server response time, Critical CSS parse and render, Render-blocking resource time. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.