Kentucky tax deadlines in 2026: filing dates and estimated payments
Deadlines that fall in calendar 2026: the 2025 return and the 2026 estimated payments. Different year? See Kentucky 2025 →
Kentucky deadlines in 2026
| 2025 individual return due | April 15, 2026 |
|---|---|
| Extended filing deadline | October 15, 2026 |
| Payment due | April 15, 2026, extension or not |
| Final 2025 estimated payment | January 15, 2026 |
| 2026 estimated payments | April 15, 2026 · June 15, 2026 · September 15, 2026 · January 15, 2027 |
Conforms to the federal deadline.
Kentucky estimated tax payments in 2026
You can reasonably expect more than $5,000 of income from which no Kentucky tax is withheld and expect to owe at least $500 for 2026 after withholding and refundable credits; if estimated tax for the year is $500 or less no payment is required.
| Q1 (2026 tax year) | April 15, 2026 |
|---|---|
| Q2 (2026 tax year) | June 15, 2026 |
| Q3 (2026 tax year) | September 15, 2026 |
| Q4 (2026 tax year) | January 15, 2027 |
| Voucher | Form 740-ES (42A740-S4 instructions) |
| Underpayment safe harbor | Withholding and credits must be at least the smaller of 90% of 2026 tax or 100% of 2025 tax (12-month return); substitute 110% for 100% if 2025 Kentucky AGI exceeded $150,000 ($75,000 MFS, not for farmers); farmers and fishermen substitute 66 2/3% for 90%. |
| Pay online | epayment.ky.gov |
Four installments; If first liable later in the year the remaining installments are 3, 2 or 1 (September 2 to December 31 liability is paid in full January 15, 2027). The file is named '740-ES Instructions (2025).pdf' but its content is 42A740-S4 (9-25) 'Instructions for Filing Estimated Tax Vouchers 2026'; the 2026 vouchers are at revenue.ky.gov/Forms/740es%202026.pdf. No estimate required if you had no Kentucky liability for the full 12-month 2025 year. Farmers/fishermen may pay all by January 15, 2027 or file and pay by March 1, 2027. Online estimated payments accept ACH only; e-filers can schedule debits.
Source: revenue.ky.gov, read September 3, 2026. “Installments for calendar year 2026 are due April 15, June 15, September 15, 2026, and January 15, 2027.”
All 51 jurisdictions in one table: state estimated tax payment dates for 2026.
Kentucky extensions
Every state's rule in one table: which states accept the federal extension in 2026.
| Does Kentucky accept the federal extension? | Yes. A federal extension is honored; no state form. |
|---|---|
| State extension form | Form 740EXT |
| Original due date | April 15, 2026 |
| Extended due date | October 15, 2026 |
| Payment | Still due April 15, 2026. The extension is to file, not to pay. Filing 740EXT does not extend the time to pay; interest and penalties apply to tax paid after April 15, 2026. |
| How to get it | If you filed a federal extension, attach federal Form 4868 to the Kentucky return; file Form 740EXT (paper or electronic) only if you owe tax with the extension or want a Kentucky-only extension. |
Source: revenue.ky.gov, read September 3, 2026. “Taxpayers who request a federal extension are not required to file a separate Kentucky extension, unless an amount is due with the extension.”
Federal deadlines in 2026
| 2025 Form 1040 | April 15, 2026 · extension October 15, 2026 |
|---|---|
| 2025 S-corp (1120-S) & partnership (1065) | March 16, 2026 |
| 2025 C-corp (Form 1120) | April 15, 2026 |
| 2026 federal estimated payments (1040-ES) | April 15, 2026 · June 15, 2026 · September 15, 2026 · January 15, 2027 |
Source: IRS Publication 509 and Form 1040-ES instructions, irs.gov.
Frequently asked questions
When are Kentucky state taxes due in 2026?
Your 2025 Kentucky individual income tax return is due April 15, 2026. If that date falls on a weekend or legal holiday, the deadline moves to the next business day. An extension moves the filing deadline to October 15, 2026, but any tax owed is still due on the original date.
When are Kentucky estimated tax payments due in 2026?
Kentucky estimated payments for the 2026 tax year are due April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027. Use Form 740-ES (42A740-S4 instructions) or pay online. The final installment for 2025 was due January 15, 2026.
Does Kentucky accept the federal extension?
Yes. A federal extension is honored; no state form. The state form is Form 740EXT. The extended filing deadline is October 15, 2026, and tax is still due by April 15, 2026.
Does a Kentucky extension give me more time to pay?
No. An extension extends the time to file, not to pay. To avoid penalties and interest, pay what you expect to owe by April 15, 2026.
Dates are the statutory deadlines that fall in 2026 and move to the next business day when they land on a weekend or holiday. Each section links to the source it was checked against. Always confirm with the Kentucky tax agency or the IRS before relying on a date. This is general information, not tax advice.