This free calculator will help you determine how much you may be able to reduce your tax debt to the IRS. The Offer in Compromise is the most popular and effective way to actually reduce the money you owe the IRS and anyone can file one. This calculator contains calculations the IRS uses to determine approval of and Offer in Compromise. Basically it is a mathematical formula to determine offer amount and is based entirely on your ability to pay. So let's get started by filling in your information below.