If you earn 1099 or self-employment income in Alabama, the IRS and the state both expect you to pay taxes as you go — in four quarterly installments rather than one April bill. This calculator estimates your 2026 quarterly payments across all three pieces: federal self-employment tax, federal income tax, and Alabama state income tax. Alabama is one of the few states that lets you deduct your entire federal income tax from your state taxable income — a large break that this calculator applies. Enter your expected net self-employment income, any W-2 wages, and your filing status to see what to send each quarter, your due dates, and how the safe-harbor rules protect you from an underpayment penalty. Everything is an estimate for planning — always confirm with the Alabama Department of Revenue before you file.
Self-employment income has no tax withheld for you, so both the IRS and Alabama Department of Revenue ask you to prepay in quarterly installments. On the federal side you owe self-employment tax (15.3% Social Security and Medicare on 92.35% of your net profit, up to the Social Security wage base) plus federal income tax on your profit after the standard deduction. On top of that, Alabama applies its own income tax.
Alabama generally requires estimated payments once you expect to owe more than $500 in state tax for the year. Alabama follows the federal schedule: April 15, June 15, September 15, and January 15. Alabama follows the standard four-installment schedule.
You avoid an IRS underpayment penalty by hitting a "safe harbor": paying at least 90% of this year's total tax, or 100% of last year's (110% if your income is higher). Alabama applies 2%/4%/5% to your federal AGI after a sliding standard deduction plus personal exemption (folded together here) and a full deduction for the federal income tax you owe. Standard-deduction amounts are from the latest published (2025) chart. Birmingham and Bessemer occupational taxes are not included. You can pay online through the Alabama Department of Revenue portal, and the calculator above breaks your total into the federal and Alabama pieces so you can send each to the right place. You can pay online at the Alabama Department of Revenue (payment portal).
For educational purposes only — not tax advice. Tax rules change and individual situations vary; confirm figures with a tax professional and the Alabama Department of Revenue before filing. State tax data last verified 2026-07-05.
Sources: revenue.alabama.gov, revenue.alabama.gov.