[See also the page: Do I Have To File?]
[Updated Feb 6, 2025]
If you are required to file, you must file even if it is past the due date. If you owe additional money, there may be penalties and interest for not paying the required amount due by the due date of the return. The penalty and interest would be a percentage of the tax unpaid by the due date.
If you are due a refund for a specific year's tax return, you must file your tax return forms within three years of the due date for that year's tax returns. For tax year 2024 (returns due on April 15, 2025), tax returns would have to be submitted by April 15, 2028, to receive your refund.
If your tax return shows that you owe money, you must file (submit) your tax forms and payment by the due date (April 15, 2025 for 2024 tax year) to avoid additional penalties and interest.
Filing an extension extends the due date of the tax return, but the due date of the payment does not change.
For more information, see IRS's "Filing Past Due Tax Returns."