I received a 1099-R for a distribution I received and had 24% tax withheld. Why do I still owe tax on it when filing?

[rjs]

You don't owe tax on the 1099-R. You owe tax on your total income, because the total amount of tax that you had withheld during the year, from anywhere, is less than the tax on your total income for the year. The tax on your tax return is not calculated separately on each source of income. It's calculated on your total income from all sources. Your total withholding is applied against your total tax.