SAN FRANCISCO, June 6 — Google plans to make available on Tuesday morning a test version of a Web-based spreadsheet program that is intended to make it simple to edit and share lists and numeric information online.

The company said that the free program, called Google Spreadsheets, was still in the experimental stage, and that while it can read and create files in the format used by Microsoft's Excel spreadsheet program, it is not compatible with many of that program's more powerful features.

At the same time, the Web search company appears to be moving ahead in its steady march toward creating its own computing universe that is an alternative to the desktop PC software business now dominated by Microsoft.

Google executives said today that the program would make it possible for Internet users to upload two common spreadsheet and data formats, Excel and C.S.V. Once the data is on Google's Web servers, it will be possible for two or more people to simultaneously edit spreadsheet documents and chat about them using Google's instant messaging program.

The new service will be able to handle several hundred formulas used to manipulate data in Excel, but it will not handle more complex functions like Excel macros, said Jonathan Rochelle, the Google Spreadsheets product manager.

"When people want to share and collaborate, we think this product fits in well," Mr. Rochelle said.

The service was developed by Google's research arm, Google Labs. The company stressed the experimental nature of the product and said the service would initially be offered only to a very limited number of users.

The introduction of Google Spreadsheets comes just months after the company bought a small Silicon Valley company called Upstart, the creator of a Web-based word-processing program called Writely.

Despite widespread speculation about whether that service would compete with Microsoft Word, Eric Schmidt, Google's chief executive, said during a recent news conference that the company had no intention of using Writely to enter the word-processing marketplace. Rather, he said, Google was hoping to integrate Web-based word-processing into many services that it was developing.

The Google spreadsheet is intended to be used by small groups of business users, or by people who now use spreadsheets as de facto database programs to keep simple lists, Mr. Rochelle said.