Software that knows its taxes can make a hard job much easier

It's worth it to professional accountants to spend $2,000 to $3,000 on some computer software for tax preparation or tax planning. Using the computer, and their own tax know-how, they can whip off a lot more tax returns every day.

But what about the individual who's not a tax whiz?

Though most of the tax software now available is geared toward the certified public accountant (CPA), there are a few programs in the $100-to-$300 range tailored for the layman. Even then, to get the full benefit from a tax software program, the user should be familiar with his computer, have a complicated enough tax return to make computer power worth it, and be fairly knowledgeable about taxes.

''As a practical matter, it's unlikely a novice tax preparer will find tax software advantageous - from either an economic or time standpoint,'' warns a CPA at a major accounting house.

Still, going ahead with full-scale computerization of taxes has benefits. One individual user said computer software chopped tax-preparation time ''from a number of weeks to a number of days.'' Tax software is also tax deductible. And if you are doing tax planning, the computer can help with things like income averaging. Also, a computer program remembers all the deductions and options, while the taxpayer may not.

Most everything from record keeping to actual preparation can be done on a personal computer. Instead of an accordion file, electronic ledgers and check recorders can keep track of deductible receipts or extra income. Most personal computers now have record-keeping programs designed for specific models, such as the $50 Checkwriter program for Radio Shack TRS-80 computers. More advanced electronic spreadsheets - such as popular VisiCalc, Lotus 123, and Multiplan - work on various kinds of personal computers and may be more than you need. Still , they are adaptable to record keeping.

''Pretty much any general ledger program will work,'' says Jan Huffman, vice-president of Management Techniques, a Boston company that sells software to accountants. ''Even as low as $50, it should do what an individual needs.''

But when it comes to looking for tax-preparation and tax-planning software, the user has to be more careful.

Dan Watt, technical editor of Personal Computing magazine, says a tax program should first of all be easy to use. ''It should structure your path with menus and prompts to help guide you through the program,'' he says. ''It should give you a chance to make corrections and let you go back to different parts of the program easily.''

One of the most important features to consider is updating. Every year, tax forms and tax rules change, and programs must change with them. Make sure updates are available for the program you buy.

Also, support and documentation can't be overlooked. The manual that goes with the program should be easy to read. And the software company that made your program should be available by phone and have in-house accountants and programmers to answer questions. If you are doing taxes at the last minute and can't make the program work, the last response you want from the company is: ''Write us a letter.''

Taxpayers should also be aware that some tax programs don't print out IRS-approved forms. The program should either do this or be able to print directly on top of a 1040. The program should also be able to handle all the schedules you need in addition to the 1040. A lot of software companies don't have state tax programs.

The best way to do tax software shopping, says Mark Elfman, an accountant with Laventhol & Horwath's tax department, ''is to take figures from last year's income tax, go to a computer store, and ask them to set up some software for you. Try it, and see how easy it is to do it.''

The number of tax programs for individuals is limited. Most software companies are still marketing to accountants, because that's where the money is. But ''there is more of a market now for individual-oriented tax software,'' says Marilynne Smith, president of Microcomputer Taxsystems Inc. in Woodland Hills, Calif. ''Our goal for the next few years is to make the smaller package better.''

Microcomputer Taxsystems is one of the few professional tax software makers which has two levels of tax preparation programs. The one for non-CPAs, called Micro-Tax Level I, sells for $195. The update is $125. It has 14 schedules and forms and runs on almost every microcomputer. The package can do some tax planning. Taxsystems also provides state programs for 17 states at $75 each.

Another popular program is Howard Software Services' Tax Preparer, for $250. It runs on the Apple and IBM computers, has a sample 1040 on it, and is easy to move around in. One complaint, as perhaps with some other systems, is inadequate answers to phoned-in questions.

In the area of tax planning, ''a little knowledge can be dangerous,'' says one accountant. But if you want to go ahead, one program recommended by users and dealers is Aardvark Software Inc.'s Personal Tax Plan, for $130. Like Microcomputer Taxsystems, Aardvark has two levels of tax planning software. The company is in the middle of improving user ease and capabilities for a new program.