What's a good Time to First Byte?
A good Time to First Byte is 800ms or lower — Google's 'good' threshold: 0.8 seconds or less. Time from request to first byte of response from the server. Excellent is 200ms or lower (Karbon target), and the minimum acceptable tier is 1.8s or lower (Google's 'poor' line: greater than 1.8 seconds).
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The three tiers Karbon grades against — and where each comes from
| Tier | Value | What it means | Basis |
|---|---|---|---|
| Minimum | 1.8s | The floor. Below this, something is broken. | Google's 'poor' line: greater than 1.8 seconds |
| Recommended | 800ms | The tier a healthy campaign should hit. | Google's 'good' threshold: 0.8 seconds or less |
| Excellent | 200ms | Top-tier performance worth defending. | Karbon target |
| Published threshold | 0.8 s | Google's 'good' TTFB threshold. Source (2025-11) | |
Lower is better for this metric.
Why Time to First Byte matters
TTFB is the baseline for all other performance metrics. A slow TTFB means everything downstream is delayed. Usually indicates server, CDN, or database issues.
Sources
The three tiers on this page are Karbon Agency's grading targets. These published figures are the outside reference points for Time to First Byte, so you can check our tiers against them.
- web.dev (Google) — Time to First Byte (TTFB) (November 18, 2025; read September 26, 2026)A TTFB of 0.8 seconds or less is good; between 0.8 and 1.8 seconds needs improvement; greater than 1.8 seconds is poor.
Where does your Time to First Byte land?
Karbon Agency grades every client campaign against these exact tiers, live on a dashboard — no guessing, no quarterly PDFs.