For all their inherent usefulness, computerized calendars can be as much of a burden as a boon. Keeping your calendar up-to-date on multiple devices and among multiple people can be annoying and time-consuming.

If you’re in a big organization on a corporate network, the calendar in Microsoft Outlook allows some of this sharing automatically. But for mainstream consumers, independent professionals and small businesses without managed networks, it’s much tougher.

One logical alternative has been Web-based calendars, which can be accessed, and thus shared, from any computer, without installing or using Outlook or any other calendar software. But these Web calendars have been primitive compared with Outlook or Apple’s iCal.

Now, Google has set out to change all that. It has entered the Web-based calendar field with a new service called Google Calendar that aims to make shareable Web-based calendars as easy and quick to use as calendar programs that live on your hard disk. Google Calendar (calendar.google.com) is still in its beta, or test, phase, but it’s already impressive.

Google is entering a crowded field. Its main rivals, like Yahoo, Microsoft and AOL, already have popular Web-based calendars. And smaller companies have launched decent offerings such as Trumba, AirSet and 30 Boxes. Google’s new calendar doesn’t yet have every feature these rivals offer, but it’s slicker and feels more like a full-fledged calendar program.

Google Calendar is free and works with numerous Web browsers, but the company advises that it works best in the newer versions of Internet Explorer for Windows, and of Firefox on Windows or Macintosh.

I have been testing Google Calendar for about a week, on both a Windows PC and a Mac, and have been comparing it with Trumba (www.trumba.com), the Web-based calendar I use and share with my assistant and my wife. One big difference: Trumba offers only limited free functionality. For sharing and certain other features, Trumba charges $100 a year.

Google calendar has most of the core features of other calendar services – month, week, day and custom views; recurring appointments; reminders. Like most of the other Web-based calendars, Google’s entry also allows you to open your calendar for others to see or even to edit. You can keep it private, share it only with designated individuals, or publish it for the entire world. It also allows you to import public calendars, or private calendars whose owners have given you permission.

Multiple calendars can be merged into a single view, and you can opt to see their entries in different colors. I added a public calendar of all Boston Red Sox games, which showed up in red, mingled with my appointments in blue.

What makes Google’s calendar stand out is its ease of use. If you want to add an appointment, you just click on a day and hour, and a simple box pops up in which you can type the event. Or you can use a feature called Quick Add to type in a phrase like, “Lunch with Katie at noon Friday at Luigi’s.” Google will add an entry on the next Friday at 12 p.m. that says, “Lunch with Katie at Luigi’s.”

If you receive an e-mail in your Gmail account that appears to include an appointment, Google offers you an option to add it to your calendar. I sent myself an e-mail that said, “Meet Edie at Umberto’s for lunch at noon on Friday” and then clicked on the new Add to Calendar option in Gmail. Google Calendar created an entry for the next Friday at noon that said, “Meet Edie at Umberto’s for lunch.”

By contrast, in Trumba and in other Web calendars, adding an event requires filling out a detailed form on a separate page. Google has this option as well, but you needn’t use it.

Moving an appointment is also a snap in Google calendar. You just drag it, as you do in many traditional calendar programs.

Google Calendar has some drawbacks. The worst one is that, in month view, it doesn’t show all of the appointments on really busy days, forcing you to go to a separate page to see all but the first four or five entries. This is really annoying if, like me, you rely heavily on the month view.

By contrast, Trumba shows every appointment in month view.

Google Calendar also can’t synchronize with a hand-held device or export its entries. And in my tests, a feature that sends reminders to a phone didn’t work. Also, like all Web-based calendars, it’s useless unless you can get online.

Still, Google Calendar is worth a try. It’s already good and should get better.

Walter S. Mossberg writes about personal technology for The Wall Street Journal.