Enterprise
Individual & Small Business
| Payment | Oklahoma due date |
|---|---|
| 1 | |
| 2 | |
| 3 | |
| 4 |
Federal 2026 estimated tax due dates, for comparison: April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027.
Who must pay Oklahoma estimated tax?
You must make equal quarterly estimated tax payments if you can reasonably expect your tax liability to exceed your withholding by $500 or more, and you expect your withholding to be less than the smaller of: 1. 70% of your current year's tax liability, or 2. The tax liability shown on your return for the preceding taxable year of 12 months. Estates and farmers (2/3 of gross income from farming) are not required to make estimated payments.
How do you avoid a Oklahoma underpayment penalty?
Timely estimates plus withholding of at least 70% of the current-year tax liability or 100% of the prior-year tax liability (12-month year). Underpayment interest is 20% per annum; none is imposed if the tax shown on the return is less than $1,000. No 110% rule.
How much should you pay?
Start with your federal estimate: the free Quarterly Estimated Tax Calculator works out your 2026 federal payments and safe harbor. Oklahoma figures its own tax, so the state amount is separate.