The IRS requires you to pay 90% of the year's tax liability or 100% of last year's obligation by January 15.

What should you do when you can't meet your obligation? Send a partial check on the due date, and attach a letter saying you cannot afford to pay the entire sum but will pay it over time.

The IRS will send you Form 9463 with a one-, two-, or three-year schedule of payments. Make sure you keep up with these payments.

The inability to pay taxes is a call of alarm. Once you handle the payments, you should take the time to analyze why your business did not generate the necessary tax payments.

Make adjustments to prevent this from happening again. You may have to cut staff, sell off unused equipment, focus on more profitable jobs, or even lower your income. --Howard Scott is a business writer and small business tax preparer in Pembroke, Mass.