Modified adjusted gross income (MAGI) is a measure of income used to determine how much of a tax-deductible contribution you may make to a regular IRA or nondeductible contribution to a Roth IRA. MAGI is also used to determine how much you can contribute to certain Coverdell education savings accounts, formerly called education IRAs. MAGI is smaller than gross income and may be larger than adjusted gross income (AGI is shown on line 37 of the 2008 IRS Form 1040.) The IRS says that MAGI and AGI are equal for most taxpayers. To calculate MAGI, add any foreign-earned income and housing exclusions (or income earned in American Samoa or Puerto Rico) to your AGI.