HostedSiteDemoHow the estimate works
Load time ≈ (size × 8 ÷ speed) + RTT × (3 + request rounds)
The first part is pure download time: megabytes times 8 gives megabits, divided by the connection speed in megabits per second. The second part is latency. Opening a secure connection takes about three round trips (DNS, TCP and TLS). Then resources are fetched in rounds: HTTP/1.1 browsers open about 6 connections per host, so 60 requests take about 10 rounds, while HTTP/2 and HTTP/3 send them over one connection in two or three rounds.
It leaves out server response time, JavaScript execution and rendering, so real pages are usually slower. It is most useful for seeing how much page weight costs you on slow connections.
How to make pages load faster
- Shrink images: serve WebP or AVIF at the size displayed. Images are usually most of a page’s weight.
- Cut JavaScript: remove unused libraries and third-party widgets; each one adds weight and requests.
- Use a CDN: a closer server means a shorter round trip on every request.
- Enable HTTP/2 or HTTP/3 and compression: most modern hosts do this by default; check that yours does.
Frequently asked questions
What is a good page load time?
Google’s Core Web Vitals treat a Largest Contentful Paint (LCP) under 2.5 seconds as good. For a full page load, under 3 seconds on a mobile connection is a reasonable target; every extra second loses visitors, especially on mobile.
Why is my real load time different from this estimate?
Real pages also spend time on server processing, running JavaScript, rendering and loading resources in sequence. This calculator estimates the network part only: download time plus connection round trips. Measure real pages with PageSpeed Insights or your browser’s Lighthouse panel.
What does RTT mean?
Round-trip time: how long a tiny message takes to reach the server and come back. It is set mostly by distance and network type. A server in another continent can add 150 ms or more to every round trip, which is why a CDN helps even small pages.