Numion homepage Measure your speed Measure your website Measure the time it takes to download any page on the internet. A collection of bandwidth calculators. SiteSpeed statistics for this website Copyright 2005 J.C. Kessels Goto Numion homepage Frequently asked questions Interesting Links Contact page, to report a problem or ask a question Copyright 2005 J.C. Kessels


PageSize Calculator

You are building a new website and want to know how large your pages can be. Do you want them to show inside 10 seconds? Or is 20 seconds acceptable? How fast are your visitors? Worldwide, national, or intranet? Use this calculator to determine the maximum pagesize you should be aiming for.

Tip: Save this page on your harddisk to use the calculator off-line.

Enter your requirements:

Maximum download time:
A generally accepted number is between 10 and 15 seconds per page. 		seconds
Number of images on the page:
Every image incurs a penalty for http overhead (see below). 		images
Number of frames:
Every frame incurs a penalty for http overhead (see below). 		frames
Speed of the average user:
For example: a 28k8 modem is 28800 bits per second. 		bits per second

Results:

Maximum size of homepage:
For html and images together. 		bytes
The calculator uses the following formula:

Maximum size of homepage =
(MaximumDownloadTime - 0.2 * (Images + Frames + 1)) * (Speed / 8) - 300 * (Images + Frames + 1)
Every image and every frame (plus the frame-startup) incurs a penalty of 0.2 seconds and 300 bytes. The time penalty is because the browser needs to send a request to the webserver for each image/frame. The 300 bytes penalty is for the http overhead that accompanies each and every image/frame.

Images are often used more than once in a website, such as the background, logo, and navigation buttons. They are loaded only once into the cache of the browser, usually on the homepage. You can therefore disregard those images on sub-pages (set the number of images to zero). The same applies to frames, even more so.