Future Media Standards & Guidelines

Download Standards v2.0

Navigate on this page:

  1. Introduction
  2. Optimising your pages
  3. Size restrictions and measurement
  4. Appendix A: Why
  5. Document History

1. Introduction

This standard gives the basic requirements and recommendations for creating pages with acceptable load times. The perceived quality of the user experience of browsing bbc.co.uk can be directly affected by the download time of its pages (how long it takes for a page to finish loading on a user's browser). The simplest metric for measuring this is the page weight limit - meaning the total weight (in KB) of an HTML page and its inline objects.

On consideration, we have identified a new method using proprietary tools that are already familiar to many web developers and designers.

For the purposes of this standard Page weight should be regarded as: 'The total amount of downloaded data from the initial page request until the loaded page is completed and stable with no ongoing downloads (not including any further data loaded as a result of user action / event e.g. mouseover, onclick, etc).'

Top of page

2. Optimising your pages

2.1 You MUST optimise the weight of your pages – pages MUST be as small as possible, whilst still supporting the editorial proposition of the page.A1

2.2 Please see the following guides below for more details on optimising your pages:

There are also tools available to help you, see the wiki page on the bbcimg service [Internal BBC document Internal BBC doc].

Top of page

3. Size restrictions and measurement

3.1 All pages on bbc.co.uk SHOULD have a maximum page weight of 500KB.

3.2 You MUST use Yahoo’s YSlow and Google’s PageSpeed with Firebug for Mozilla’s Firefox to test your page’s download performance.

3.3 Pages of 500KB or less MUST have an average performance score (average of scores from YSlow and PageSpeed) of 60 or more.

3.4 Pages of 500KB to 750KB or less MUST have an average performance score (average of scores from YSlow and PageSpeed) of 70 or more.

3.5 Pages of 750KB to 1MB MUST have an average performance score (average of scores from YSlow and PageSpeed) of 80 or more.

3.6 Your pages MUST NOT be larger than 1MB. If you require a page that is larger than 1MB you MUST apply for an exemption from the Editor, Standards and Guidelines.

Top of page

Appendix A: Why

  • A1. If you can make changes to the implementation of a page which decrease its weight (or download size) without adversely affecting the content, function and presentation of the page, the resulting page is considered to be of better quality and one that delivers an improved user experience.

Top of page

Document History

DateVersionChangeAuthor
20/10/2010 v2.0 Major revision. Removal of absolute download size limit requirements and introduction of new metric based on YSlow and PageSpeed scores. Ed Lee
03/06/2008 v1.1 Added additional download weight of 300KB for Barlesque-based sites, and details about optimising pages for caching. Victoria Jolliffe
22/03/2004v1.00-external v2Rebranded BBCi => bbc.co.uk Jonathan Hassell
01/10/2003v1.00-externalRemoved retrospective section (not appropriate to externals); links to research docs; triggers sectionJonathan Hassell
12/09/2003v1.00Standard renumbered as 1.00 on approval by Standards ExecJonathan Hassell
02/09/2003v0.35Final version of standard, after changes required by Design Forum on 26/08/2003 and Tech Forum on 29/08/2003Jonathan Hassell
29/08/2003v0.34Final updates before Tech Forum 29/08/2003 (after stats comments by MattB, NickH, PaulH, JamesC) – changes in: (1.1) "on consideration..." paragraph; (1.3) removal of "be google"; (1.4) more clarity on Flash; (2.2) removal of hints and tips to external doc; (3) re-expression of formula; (triggers) 6 months is now 3 months; (1.4) now includes 200KB timings for poor ISP as wellJonathan Hassell
28/08/2003v0.33Updates after comments from Matt Blakemore: reinforced quality = optimised (not small); moved calculation stuff to later in doc and stated it isn't perfect yet; info on size of header; triggers on compressibility of text and table rendering; exceptions for printable pages and a/v streamsJonathan Hassell
22/08/2003v0.32Updates after download group meeting on 20/08/2003Jonathan Hassell
13/08/2003v0.31Added question re objects (in formula) => unique objects?Jonathan Hassell
23/07/2003v0.3Updated after Tech Forum meeting of 23/07/2003 and JH's questions after looking at PH's 3000 pages spreadsheet of 22/07/2003Jonathan Hassell
18/07/2003v0.2Updated after Download Group meeting of 17/07/2003 (still requires more research/justification of limits before being proposed as a standard)Jonathan Hassell
15/07/2003v0.1First draft of this standard – summary of agreements from Download Group meetingsJonathan Hassell, Nick Holmes

Document editor: Editor, Standards & Guidelines. If you have any comments, questions or requests relating to this document, please contact the Editor, Standards & Guidelines.

Like all other Future Media Standards & Guidelines, this page is updated on a regular basis, through the process described on About Standards & Guidelines.

Top of page

bbc.co.uk navigation

BBC © 2012 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.