Computers: Opening up a world of possibilities: One of the big advantages of spreadsheets is being able to do 'what if' forecasts. Janet Swift looks at the Windows options

IF YOU THINK of the word processor as replacing the typewriter, you can think of a spreadsheet as being the equivalent of a pencil, calculator and the 'back of an envelope'.

Windows, the PC-compatible's graphics-based operating system, has a calculator program for one-off calculations, but when you want to keep track of 'the workings' you need a spreadsheet. This allows you make a note of your starting values, perform some calculations and to see the answers.

The spreadsheet is an ideal way of playing with numbers and comes into its own when calculations are difficult. Most spreadsheets have a wide range of built-in functions, so, for instance, if you want to work out the total return on an investment at a given interest rate over a period of time, you can do so in a single step.

If you want to keep financial records, then consider the spreadsheet as the electronic equivalent of a ledger book where the columns can be automatically totalled and you never need doubt the arithmetic.

But while the spreadsheet has become standard in business, its role at home is less obvious. The typical examples quoted to justify the need for one are keeping track of your bank balance and discovering what your mortgage repayments should be. However, the advent of personal finance programs, such as Microsoft's Money and Intuit's Quicken, means that the spreadsheet is no longer an obvious tool if all you want are answers to standard question.

If, however, you are the sort of person who prefers to work things out for yourself, then a spreadsheet is the tool you need.

The advantage of the spreadsheet is its flexibility. It will help you make sense of information of every type - it handles lists of numbers, dates and words with equal ease. Indeed it is so easy that you can use it for chores that you would otherwise avoid.

For example, if you want to find out which is the bargain buy from a bewildering range of possibilities - say, for instance, competing computer systems all with slightly different specifications - then a spreadsheet can be used to make a list of options complete with prices, discounts and total costs including delivery. You can work out anything you need simply by entering the calculation.

If you change the basic figures - a higher discount or whatever - then the calculations and results are updated instantly. The first time you see this happen it looks like magic - and from the point of view of anybody who would otherwise have had to perform the same task with a pocket calculator, it is magic.

Spreadsheet magic is now better than ever in that programs anticipate what you would previously have had to tell them. For example, in Lotus 1-2-3 for Windows all you have to do to produce a list of the months of the year is to type in just one word. You start 'January'. and it will automatically carry on February, March and so on. You can waste a lot of time just trying to find a sequence that the program cannot predict automatically.

Another role for the spreadsheet is in exploring what might happen given different sets of conditions. This means you can investigate questions like: 'How much will my savings buy me in 10 years time if the interest rate is 8 per cent or 6 per cent or 4 per cent and inflation is 1 per cent, 2 per cent or 5 per cent?'

Tables of figures often seem dry and indigestible. A spreadsheet can give them colour and add impact. You can produce colourful and informative charts with the minimum of bother and can make printed output attractive using different typefaces and graphics.

The most important criteria for home users is ease of use and on the whole spreadsheets are easier to use than to explain. Just five minutes watching someone use one - or following through the simple examples that the programs provide - is all that is needed to get you going. Windows spreadsheets are particularly easy to use because you can use the mouse to point at the data you are interested in.

There are three main Windows spreadsheets. The one with the brand name that means 'spreadsheet' to most users is Lotus 1-2-3. This has a long track record in the pre-Windows era, but until recently this was perhaps more of a disadvantage.

The reason is that starting from an existing product is not the best way to develop something radically new. The latest incarnation, version 4 for Windows, has finally progressed far enough away from its origins as a Dos program - designed to work from the PC's text- based operating system - to be able to resume its position as one of the leading spreadsheets - but competition is tough.

Excel is Microsoft's spreadsheet. It has always been at the forefront of Windows technology - not surprising as the two programs come from the same company - and it has been responsible for introducing some of the ideas that make current spreadsheets so easy to use, such as a 'sum' function that automatically recognises the numbers that you want to total.

Quattro Pro version 5, a sophisticated spreadsheet from Borland, has a smaller share of the market than the other two, but it has just as many good features and to my mind it has the best thought-out structure. Perhaps the only problem is that all Windows spreadsheets are 'full featured'. This is a polite way of saying that you are unlikely to use more than 10 per cent of their capabilities. If you look at what the software manufacturers would claim as key features they go far beyond the everyday requirements of the average business user and are well in excess of the home user's wildest dreams.

For example, Lotus 1-2-3 release 4 makes a selling point of having a 'Version Manager' which allows the sharing of ideas with co-workers on a network. This is good news for merchant bankers, but good news for them may leave the rest of us unmoved.

In addition, all spreadsheets have sophisticated analysis options that most users never explore, let alone use. The main drawback of these surplus features is that they fill up your machine's disk storage and slow down the part of the program that you do use - causing problems if your machine is not powerful enough to cope.

If you want a cut down version of a Windows spreadsheet you might be surprised to discover that there is no such product. The nearest alternative is an all-in-one package such as Microsoft Works for Windows. This gives you almost all the spreadsheet functionality you are likely to need and is not too greedy in its demands for resources.

If you want a full spreadsheet, but not at the corporate price tag they usually command, my recommendation would be Quattro Pro Standard which at its current offer price of about pounds 50 (0800 212727) has to be described as a 'best buy'.