Kansas corporate income tax, tax year 2026

Source-cited draft. Built from K.S.A. 79-32,101, 79-32,103, 79-32,107, 79-32,110, 79-32,110c, 79-32,141 and 79-32,142 (Kansas Revisor of Statutes), KDOR Notice 25-06, the KDOR 2025 Corporate Tax Booklet and the KDOR corporate income and franchise tax pages, read on 2026-10-28. No accountant has reviewed it. Do not file, pay, amend, or take a tax position from it without review by a qualified Kansas professional.

Tax year: the corporation's federal tax year (calendar or fiscal). Authority: Kansas Department of Revenue (KDOR). Currency: US dollars. Covers Kansas corporate income tax (Form K-120), S-corporation treatment (Form K-120S) and the bank privilege-tax carve-out.

See also: ks-income-tax, ks-transfer-pricing, ks-cross-border.

Who this applies to

• All corporations doing business within or deriving income from sources within Kansas who are required to file a federal income tax return must file a Kansas return, whether or not tax is due (KDOR Corporate Income page; 2025 Corporate Tax Booklet).
• Subchapter S corporations for federal purposes are automatically S for Kansas and must file as such (Form K-120S) — except banks, savings and loan associations, and trust companies, which are barred from S status for Kansas and file the privilege tax return (K.S.A. 79-1107/1108) instead of K-120 (KDOR FAQ).
• Short-period returns: required for Kansas whenever required federally (KDOR FAQ).
• 501(c)(3) nonprofits: no Kansas copy of federal Form 990 is required; most still file the Secretary of State annual report (KDOR FAQ).
• Franchise tax: repealed. No Kansas franchise tax for tax year 2011 and after; the old KDOR tax (max $20,000, 0.03125% of net worth in its final year, Form K-150) is historical only. A separate $55 Secretary of State filing fee with the annual report still applies (KDOR Franchise page).

Rates, bands and thresholds

Item	Rate or amount	Tax year	Source
Normal tax	4% of Kansas taxable income	2026	K.S.A. 79-32,110(c)(1)
Surtax	3% of Kansas taxable income in excess of $50,000 (one surtax exemption per corporate taxpayer)	2026	K.S.A. 79-32,110(c)(2); 2025 Corporate Tax Booklet, line 30 instructions
TY2026 rate reduction	None — FY2025 adjusted collections did not exceed inflation-adjusted base-year revenues, so the Secretary published no reduction	2026	KDOR Notice 25-06
Future reductions	79-32,110c (SB 291 mechanism, L. 2025 ch. 116): surtax decreases only until combined normal + surtax = 4%; 79-32,110d adds a corporate-receipts trigger from FY2028	2027 on	K.S.A. 79-32,110c
Estimated tax threshold	Required if Kansas liability is reasonably expected to exceed $500	2026	K.S.A. 79-32,101(a)(2)
Extension payment	90% of the tax must be paid by the original due date to avoid the late-payment penalty	2026	KDOR Corporate Income page
Franchise tax	None for tax year 2011 and after; Secretary of State filing fee $55	2026	KDOR Franchise page

Correction: the v0.1 draft carried "commonly cited as 4% first $50,000 and 12% above" — the 12% figure is obsolete (pre-2022 law). Current law is 4% + 3% surtax over $50,000 = 7% marginal on income above $50,000.

The taxable base

Item	Rule	Source
Base	Federal taxable income with Kansas modifications (K.S.A. 79-32,138); Kansas-source income for multistate filers	2025 Corporate Tax Booklet
Apportionment	UDITPA three-factor formula (property / payroll / sales, equal-weighted); K.S.A. 79-32,141 gives the director allocation authority for affiliated or controlled groups	Booklet; K.S.A. 79-32,141
Combined / consolidated	Federal-consolidated groups with all-Kansas income must file consolidated; the director may permit or require it for affiliated groups (Schedule K-121 mechanics per Booklet)	K.S.A. 79-32,142; Booklet
Banks	Privilege tax return (79-1107/1108), not K-120	KDOR FAQ

Deadlines and filing

Obligation	When	Source
Form K-120 / K-120S, calendar-year filers	April 15 following the tax year ("Payment of any liability shall be due April 15, 2026" for 2025)	2025 Corporate Tax Booklet
Fiscal-year filers	15th day of the 4th month after year end; Kansas conforms to federal due dates	Booklet
Extension	"Kansas accepts the federal extension of time and will follow accordingly. The extension of time is to file the return not pay the tax. Ninety percent of the tax must be paid by the due date to avoid late payment penalty"	KDOR Corporate Income page
Estimated tax (Form K-120ES)	Installments April 15, June 15, September 15 and December 15 (the corporate 4th installment is Dec 15, not Jan 15). First-year Kansas filers are exempt from estimates and the underpayment penalty	K.S.A. 79-32,103(a)(1); Booklet

Penalties and interest

• Late-payment penalty is avoided only if 90% of tax is paid by the due date (KDOR Corporate Income page, quoted above).
• Estimated-tax underpayment: a penalty at the delinquent-tax interest rate of K.S.A. 79-2968(b) on the shortfall, measured against 90% of the tax shown on the return; not added if it does not exceed $1 (K.S.A. 79-32,107(a); K.S.A. 79-2968).
• The late-filing addition and the current interest-rate value are listed under Not yet confirmed.

Cross-border points

• Non-Kansas corporations with Kansas-source income file K-120 and apportion (see ks-cross-border).
• No Kansas franchise or gross-receipts tax stacks on top (franchise repealed, KDOR Franchise page).
• The treatment of S-corporation shareholders, including nonresident shareholders, is listed under Not yet confirmed.

Worked examples

Example 1: C corporation with 80% Kansas apportionment

A C corporation has $120,000 of federal-basis unitary income and a Kansas apportionment factor of 0.80. Kansas taxable income is $96,000. Normal tax is 4% of $96,000 = $3,840. The surtax is 3% of the $46,000 above the $50,000 surtax exemption = $1,380. Total Kansas tax $5,220.

name: KS corporate tax statutory rates
inputs:
  income: 120000
  factor: 0.80
  normal: 0.04
  surtax: 0.03
  exemption: 50000
steps:
  - ks_income: income * factor
  - band1: ks_income * normal
  - band2: max(ks_income - exemption, 0) * surtax
  - tax: band1 + band2
expected:
  ks_income: 96000
  band1: 3840
  band2: 1380
  tax: 5220

Example 2: extension safe harbor on the same facts

The corporation extends via federal Form 7006. The extension covers filing, not payment, so 90% of the $5,220 — $4,698 — must be paid by April 15 to avoid the late-payment penalty; the $522 balance follows with the return.

name: KS 90% extension payment
inputs:
  tax: 5220
  safe: 0.90
steps:
  - must_pay: tax * safe
  - balance_due: tax - must_pay
expected:
  must_pay: 4698
  balance_due: 522

Ask the client first

1. Federal filing status (C, S, bank / thrift / trust company)? It decides K-120 vs K-120S vs the privilege return.
2. Kansas nexus footprint: property, payroll and sales by state? It drives the apportionment factor.
3. Affiliated group members in other states? Consolidated-return exposure under 79-32,142.
4. Was 90% of the tax paid by the unextended due date before relying on the federal extension?

Sources

Source	URL	Read on
K.S.A. 79-32,110 (rates: 4% normal + 3% surtax over $50,000)	https://ksrevisor.gov/statutes/chapters/ch79/079_032_0110.html	2026-10-28
K.S.A. 79-32,110c (rate-reduction mechanism; surtax floor at combined 4%)	https://ksrevisor.gov/statutes/chapters/ch79/079_032_0110c.html	2026-10-28
KDOR Notice 25-06 (no rate reduction for tax year 2026)	https://www.ksrevenue.gov/taxnotices/notice25-06.pdf	2026-10-28
KDOR 2025 Corporate Tax Booklet (April 15 due date, K-121 mechanics, three-factor formula, first-year estimate exemption)	https://www.ksrevenue.gov/corpbook25.html	2026-10-28
K.S.A. 79-32,101 (estimated tax, $500 threshold)	https://ksrevisor.gov/statutes/chapters/ch79/079_032_0101.html	2026-10-28
K.S.A. 79-32,103 (installments Apr 15 / Jun 15 / Sep 15 / Dec 15 for corporations)	https://ksrevisor.gov/statutes/chapters/ch79/079_032_0103.html	2026-10-28
K.S.A. 79-32,107 (underpayment penalty at the 79-2968(b) rate, 90% measure)	https://ksrevisor.gov/statutes/chapters/ch79/079_032_0107.html	2026-10-28
K.S.A. 79-2968 (interest on delinquent taxes)	https://ksrevisor.gov/statutes/chapters/ch79/079_029_0068.html	2026-10-28
K.S.A. 79-32,141 (allocation authority, controlled groups)	https://ksrevisor.gov/statutes/chapters/ch79/079_032_0141.html	2026-10-28
K.S.A. 79-32,142 (consolidated returns)	https://ksrevisor.gov/statutes/chapters/ch79/079_032_0142.html	2026-10-28
K.S.A. 79-32,138 (Kansas taxable income of corporations; addition and subtraction modifications)	https://ksrevisor.gov/statutes/chapters/ch79/079_032_0138.html	2026-10-28
KDOR Corporate Income (filing duty, S auto-status, bank carve-out, 90% extension rule)	https://www.ksrevenue.gov/bustaxtypescorp.html	2026-10-28
KDOR FAQ (S status, banks, short periods, 501(c)(3))	https://www.ksrevenue.gov/faqs.html	2026-10-28
KDOR Franchise Tax (repealed 2011+; $55 Secretary of State fee)	https://www.ksrevenue.gov/bustaxtypesfranchise.html	2026-10-28

Not yet confirmed: the late-filing addition percentage under the K.S.A. 79-3228 series; the current interest-rate value under K.S.A. 79-2968(b); Kansas taxation of S-corporation shareholders' distributive share (cited in v0.2 as K.S.A. 79-32,139, not archived) and the form nonresident S-shareholders file (K-40 vs K-40PN).

Contributed by Jeff Watts.