Hear that loud ticking? It’s the clock running out on your window of time to get your taxes done – and save yourself some money if you’re due a refund, or pull together the cash you’ll need if you owe.

Whether you’ve not filed your taxes yet because you’re too busy or simply dread the outcome so much, it’s time to tackle the task. The April 18 deadline (you get a few extra days this year because April 15 is a holiday in the District of Columbia) is not just a suggestion. If you owe nothing, the Internal Revenue Service won’t penalize you for filing late. But if you do owe, and miss the deadline, you’ll pay penalties for every day you’re late.

You can take off some of the pressure by “ballparking” your tax burden prior to filling out the forms. Look for an online tax estimator to help you get an idea of whether you can expect to pay more, or get a refund.

An online estimator will ask you to fill in such basic information as your age and filing status, income (from box 1 on your W-2), spouse’s income and dependant information. Based on the answers you provide, the tax estimator can give you an idea of how much you might owe (so you can start saving your pennies for April 18) or how much of a refund you might get (so you can start planning what you’ll do with the windfall).

Of course, an estimator can’t factor in every possible tax deduction you may qualify for, so your next step will be to get down to business. Gather all your pertinent tax records in one place (if you haven’t done so already), consult with the IRS’s website to see what filing form you should use, and set aside a block of time to focus on your taxes. One way to ensure you take advantage of every available deduction is to enlist the aid of a paid tax preparer.

If, however, your tax situation is simple enough, you can probably get by doing the work yourself using tax software. Many tax preparers offer free online software that walks you through the basics of preparing your own tax return. These companies also often allow you to pay a nominal fee for their expert help if you have a question that isn’t answered by the software program.

If you just can’t get your taxes done by April 18, you can ask for an extension, which will give you until Oct. 17, 2011 to file your 2010 tax return.

Finally, one more piece of advice: If you’re facing a big tax bill and won’t have the money to pay it in full by April 18, think twice before using your credit card to pay your tax burden. Instead, get in touch with the IRS and ask for a payment plan. You’ll almost certainly be able to negotiate a better deal than you would get paying the double-digit interest most credit cards are charging these days.