What is Time to First Byte (TTFB)? - Definition & Meaning Simplified

Time to First Byte (TTFB)

Time to First Byte (TTFB) is the exact measurement of the delay between a browser requesting a webpage and receiving the very first byte of data from the server. It is the foundational metric of page speed; if the TTFB is slow, every subsequent Core Web Vitals metric (like FCP and LCP) will fail. A slow TTFB is usually caused by inadequate web hosting, complex database queries, or bloated application logic. Achieving a TTFB of under 200 milliseconds requires premium hosting infrastructure, aggressive server-side caching, and a globally distributed CDN.

Time to First Byte (TTFB) Simplified

Time to First Byte is the delay between when you click a link and when the website’s computer actually starts sending data to your screen. If the server is slow, your entire website will be slow, which frustrates users and destroys your SEO rankings.