If you earn 1099 or self-employment income in Oklahoma, 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 Oklahoma state income tax. Oklahoma's brackets are not adjusted for inflation, and most self-employment income lands in the top 4.75% bracket, which starts at just $7,200 (single) / $14,400 (joint) for 2025. 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 Oklahoma Tax Commission before you file.
Self-employment income has no tax withheld for you, so both the IRS and Oklahoma Tax Commission 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, Oklahoma applies its own income tax.
Oklahoma generally requires estimated payments once you expect to owe more than $500 in state tax for the year. Oklahoma follows the federal schedule: April 15, June 15, September 15, and January 15. Oklahoma 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). Oklahoma applies graduated rates topping out at 4.75% (2025) to your federal AGI after the standard deduction ($6,350 single / $12,700 joint) and a $1,000 personal exemption per person. For 2026 Oklahoma moves to three brackets with a 4.5% top rate, which this page does not yet reflect. You can pay online through the Oklahoma Tax Commission portal, and the calculator above breaks your total into the federal and Oklahoma pieces so you can send each to the right place. You can pay online at the Oklahoma Tax Commission (payment portal).
For educational purposes only — not tax advice. Tax rules change and individual situations vary; confirm figures with a tax professional and the Oklahoma Tax Commission before filing. State tax data last verified 2026-07-05.
Sources: oklahoma.gov, oklahoma.gov.