You don’t need a spreadsheet to calculate the cost of the wide array of Web-based spreadsheet instruction and support resources that are available: Most are available gratis. Here’s a rundown of some of the best free sites out there, with their strengths and weaknesses.

1) Joseph Rubin’s ExcelTip.com (www.exceltip.com)

Arguably the most popular online resource for Excel support is ExcelTip.com. The site, which claims to register over eight million hits per month, allows users to search for Excel advice and shortcuts by category. The site also features the “Excel Tip of the Hour” (such as converting time values from one time zone to another) as well as a forum in which users can exchange thoughts, seek support and help fellow spreadsheet users. Joseph Rubin, ExcelTip.com’s founder, is a CPA with more than 25 years of experience as a CFO and controller. Rubin has also run his own CPA practice.

2) Allen Wyatt’s Excel Tips (exceltips.vitalnews.com)

Allen Wyatt, an Excel expert and author, runs a site that includes more than 1,700 spreadsheet-related articles and tips categorized across scores of topic areas, such as add-ins, charts, conditional formatting and pivot tables. Visitors can also subscribe to a pair of RSS feeds that will deliver daily and weekly Excel advice directly to their computers. The site’s depth, practical advice and clear and coherent explanations combine to make it the No. 2 pick.

3) MrExcel.com (www.mrexcel.com/articles.shtml)

Site visitors will find over 500 Excel-related articles created by MrExcel.com and various other Web sites. The items cover a wide range of topics and are organized by category. Visitors can learn how to add a trendline in three clicks, how to create a better chart, or how to automatically add a character to a cell. The site also includes various Excel add-ons collected from across the Web.

4) MIStupid.com (mistupid.com/tutorials/excel)

While most Excel-related Web sites offer only static text and graphics, MIStupid’s elegant step-by-step tutorials come in the form of audio-supported animations. The approach helps make complex and tricky topics, such as concatenating cells, something that’s really not stupid at all. The downside is that the site features only 16 tutorials, as opposed to the dozens or even hundreds of tips and examples provided by the other sites on this list. On the other hand, the 16 tutorials are very good.

5) Contextures (www.contextures.com/tiptech.html)

This site features a substantial, well-organized selection of Excel tips and advice presented in both text and video formats. Topics include filters, functions, scenarios, data validation, pivot tables, conditional formatting, and user forms. A detailed introduction to conditional formatting, including video and a sample file, is but one of the gems that can be found on this site. Sample spreadsheets are also available.

6) DataPig Technologies (www.datapigtechnologies.com/ExcelMain.htm)

This is an entirely visually-oriented Excel support site. DataPig Technologies offers dozens of videos that explain nearly every aspect of Excel. Most of the videos are free, but a $25 fee provides unlimited access and the ability to save the tutorials to your hard drive, CD or DVD. The Flash-based videos, such as the one on creating a histogram chart, present an animated Excel spreadsheet featuring a flying finger that shows users which menus to open, the key features to select, boxes that should be ticked and how and when to enter data, among other steps.

7) The European Spreadsheet Risk Interest Group (www.eusprig.org)

EuSpRIG was founded in 1999, when researchers from the Northern U.K. chapter of the Information Systems Audit and Control Association (ISACA), the University of Wales, Cardiff and the University of Greenwich came together to address problems of business risk associated with spreadsheet errors. To find the free gold on this Web site, scroll down toward the bottom until you reach the “Downloads” and “News” areas. Here you’ll find research papers related to spreadsheet risk issues and a bone-chilling archive of news stories on spreadsheet errors. Particularly useful are the Spreadsheet Auditing for Free presentation, which show users how to conduct a no-cost Excel audit, and How do You Know Your Spreadsheet Is Right? guide to error detection and prevention.

8) Ron’s Excel Tips (www.rondebruin.nl/tips.htm)

This simple online resource provides straightforward answers to over 50 common Excel problems. The site also provides a respectable selection of Excel add-ins, designed to make users’ spreadsheets cleaner, accurate and more useful. (Such as the Google Search add-in, which provides a user-friendly way of searching Excel newsgroups). The site is owned and managed by Ron de Bruin, a Dutch Excel hobbyist who has written extensively on spreadsheet topics.

9) BeyondTechnology (www.beyondtechnology.com/tips.shtml)

BeyondTechnology, a Houston-based software development and consulting firm, offers a limited selection of “power tips” that are designed to help users resolve a series of common Excel problems. The site’s layout is confusing, and the information base isn’t particularly deep, but it’s still worth a visit for help on topics ranging from charting dynamic data to preventing duplicate entries.

10) Microsoft Excel (www.office.microsoft.com/excel)

In any top ten Excel resource must come Microsoft’s own site and the support it provides. While hardly “hidden” from users, many simply forget to take advantage of it (or, possibly, are turned off by the sign-in that’s required). That’s a shame, because Microsoft’s site in many cases qualifies as the first stop in looking for a fast answer to a pressing Excel question. The site provides a deep knowledge base, covering hundreds of topics, for any recent Excel version. Also be sure to check out the Excel webcasts, recorded at live events by Microsoft Office experts. These offerings, covering topics ranging from time-saving tips to creating “fabulous” charts, can be viewed at a user’s own pace and include presentation slides and audio.