No Child Tax Credit for Illegals Act of 2025This bill extends and expands the Social Security number (SSN) identification requirements for claiming the child tax credit. The bill also provides that the omission of a correct SSN related to a child tax credit claim is to be treated as a mathematical error for certain purposes.Under current law, to claim the child tax credit, a taxpayer must provide a work-authorized SSN (issued prior to the due date of the federal income tax return) for each qualifying child. Beginning in 2026, to claim the child tax credit, a taxpayer must provide a valid taxpayer identification number (issued on or before the due date of the federal income tax return) for each qualifying child.Under the bill, to claim the child tax credit, a taxpayer must provide a work-authorized SSN (issued before the due date of the federal tax return) for (1) each qualifying child; and (2) the taxpayer, the taxpayer and the taxpayer’s spouse (if filing jointly), or either the taxpayer or the taxpayer’s spouse (if either is a member of the Armed Forces).Finally, the bill provides that the omission of a correct SSN related to a claim for the child tax credit is a mathematical error for purposes of certain tax assessment and collection procedures.