You had no tax liability for the prior year if your total tax was zero.

Your total tax was zero if the line labeled "total tax" on Form 1040, U.S. Individual Income Tax Return or Form 1040-SR, U.S. Tax Return for Seniors was zero, or if your gross income was below the threshold required to file an income tax return. See Who Must File in Publication 501, Dependents, Standard Deduction and Filing Information, for information on filing requirements for most taxpayers.

For this exception to apply, two additional requirements must be met:

• Your prior tax year was a taxable year of 12 months.
• You were a citizen or resident of the United States throughout your prior tax year.