My checking account used to be a dark, murky enigma. Every month, money went in, and money came out. I just sort of trusted that everything would work out OK, but I never really knew what was going on in there. (Sometimes I heard strange noises ...)

Now, thanks to a little ingenuity, I've dragged my beastly budget out into the light of day. At a glance, I know exactly how much I've spent for the current month, how that matches up with what I planned to spend, and -- most importantly -- how much I can still spend without breaking the bank. Best of all, I never even have to touch a calculator. A simple spreadsheet does all the work for me.

This one's admittedly a bit more ... uh, let's be polite and say "detail-oriented" ... than the automatic checkbook I posted last week. But just a bit of elbow grease up front will give you a lot more financial peace of mind for months, even years, to come.

You can use this file with a variety of spreadsheet programs, including Excel and Numbers for the Mac. Don't have any spreadsheet software at all? Our file should work with free options like OpenOffice.org, too -- or, if you use Google Docs, you can upload the file right back to your own account.

Got the file? Here's how to customize it:

1. First, you'll need to figure out how much money you take home each month. (OK, I lied, you will need a calculator. But only briefly!) If you get two paychecks every month, just double your paycheck amount, and you're good to go. If you get paid once every two weeks -- and yes, there is a difference -- multiply that number by 26, then divide by 12. If your income's less predictable than this, just make your best guess; you can always refine it later. When you're finished, enter your monthly take-home pay into cell C1.
2. In column A, under the "Budget Item" header, enter all the regular bills you pay each month: housing, food, gas, etc. Then enter the corresponding budgeted costs for each item -- how much you know you'll pay, or expect you'll pay -- in column B. We've set up a few sample items for you, but feel free to change them to suit you. As you fill in column B, you'll see the figures in column C change to reflect each expense.
3. In column D, type in how much you actually spend for each item in your budget. Predictable items, like rent, you can go ahead and fill in now. Expenses that change from month to month, like your cell phone bill, you can enter as each bill arrives. (For now, however, leave the spaces for Food and Gasoline alone; we'll get to those shortly.) Column E will keep track of how much money you actually have left, so you can easily compare it to your budgeted spending.
4. Under columns F and G, enter all the other non-budgeted things you spend money on in the course of the month, and how much they cost: Meals in restaurants, trips to the movies, those books you bought online, etc. If saving paper receipts is too much of a hassle, you can use your online bank once a week or so to look up how much you spent and where.
5. At the bottom of column G, the Budget Left and Actual Left figures will tell you how much room you have remaining in your budget, and how that compares with the actual money you have left to spend.
6. But wait! There's more! Since we usually pay for groceries and gas several times a month, adding up the costs can be tricky. Scroll sideways to column J, where you can punch in up to five different grocery bills and five tanks of gas. The spreadsheet will add up the totals for you, and put them in the appropriate spots under "Actual Cost" in column D. As you add new bills, the totals and all the other numbers will automatically adjust, keeping you on top of your spending.

Once you've set up your budget, it's easy to maintain. Just clear out the "Other Items" section under columns F and G, and the gas and grocery amounts in column J, at the end of every month. You can also make any changes to the actual costs in column D as needed. And feel free to tweak the budget items in columns A and B to see whether there's a better way you could be spending your monthly paychecks. (Cut back on the cable bill, and voila! You've got more money to put into savings.)

Sure, it takes a little work to get going, but we've done our best to make it easy for you. With this spreadsheet at your command, you'll spend less time worrying about whether you're about to bust your budget, and more time knowing that your money's working for you -- and not the other way around.