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Performance

Why are there so many timing numbers?

Loading a page is not one step, it is a relay. Splitting it out shows you exactly where the slow bit is. Hover or tap each leg of the race below.

The four legs of the relay

One visit to your site is really four short sprints run back to back. Each leg has its own clock, its own usual suspects, and its own fix.

~30ms
~60ms
~140ms
→ Total

TTFB, time to first byte

How long after the request the server started sending the page. This is the clearest signal of whether your backend is fast or slow.

Think of it like: The moment they start talking. This is the longest, most revealing leg of the race.

Each leg hands the baton to the next. Total time is the whole race, start to finish.

Averages lie a little; P95 tells the truth

We boil all those checks down to two numbers, and they disagree just often enough that you should read them together.

Average

The mean total time across every check in the window. A handful of slow checks can drag this up, so always read it next to P95.

Real world: like your average commute. Fine on a normal day, but it hides the morning you sat in traffic for an hour.

P95

95% of checks finished faster than this number; the worst 5% were slower. P95 catches the bad-day-for-some-users cases an average hides.

For your site: if P95 is high, 1 in 20 visitors is having a sluggish time, often enough to lose the sale.
So what counts as fast?

For TTFB, under 500 ms is good and under 200 ms is great. For total time, under 2 seconds feels snappy on broadband and under 1 second is what shopping carts and SaaS dashboards aim for. Mobile networks add roughly 100 to 300 ms on top, so design for that.

TTFByour site: 180ms
0ms500ms1s+
Total loadyour site: 1.4s
0s2s4s+
Slow is often just down in slow motion

A site that keeps getting slower rarely stays merely slow; sooner or later it tips over into a proper outage. The uptime guide explains what those DOWN labels mean when it does. And if you are wondering how your own site would run this relay, run an instant check and see every leg timed in a few seconds.

Now try it on your own site

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