K-120S: Partnership or S Corporation Income Tax Return (2025)
Kansas · Kansas DOR · Used for tax years 2025
Form K-120S is the 2025 Kansas Partnership or S Corporation Income Tax Return. It reports federal income, Kansas adjustments, and income allocated or apportioned to Kansas. For entities electing to be taxed at the entity level, it also calculates tax due, payments, and any refund
Who files this form
Form K-120S is the Kansas Partnership or S Corporation Income Tax Return for tax year 2025. The form asks you to identify the filer as a partnership or an S corporation.
It also includes an election to pay tax at the entity level. The supplied form does not state the full rules for determining which entities must file.
What you'll need
The form asks you to enclose:
- Pages 1 through 4 of your federal return, plus page 5 if filing as a partnership.
- Federal Schedule M-1 and Schedule M-2.
- Federal schedules supporting Kansas modifications.
- An organizational chart showing all partnerships, S corporations, and taxable entities.
Depending on your entries, also include:
- Required schedules supporting income additions, subtractions, nonbusiness income, and other items marked “schedule required.”
- Schedule K-121S if using the combined income method.
- A mileage apportionment schedule if using common carrier mileage.
- The authorization letter and schedule if using alternative or separate accounting.
- Applicable schedules for Kansas expensing recapture or deductions.
- Separate schedules for estimated tax paid and amounts credited forward, and for other tax payments.
Have each partner’s or shareholder’s name, address, tax identification number, ownership percentage, and income distribution information available to complete Part II.
How to file
Complete the filing information, income calculations, and applicable schedules. Part II must be completed for all partners or shareholders. Complete Part III for individual or fiduciary partners or shareholders who elected to pay tax using Form K-120S.
Sign and date the return in the officer signature area and include the required attachments. Do not staple.
Mail the return to:
Kansas S Corporation Income
Kansas Department of Revenue
PO Box 750260
Topeka, KS 66699-0260
If sending a payment, complete Form K-120V and enclose it with your payment.
Common mistakes
- Stapling the return. The form says “DO NOT STAPLE.”
- Leaving partners or shareholders out of Part II. This schedule must cover all partners or shareholders. If there are more than 12, submit an additional schedule similar to the one on the form.
- Using the wrong Part II columns. Individual partners or shareholders complete columns 1 through 8. All others complete columns 1 through 5.
- Using the wrong apportionment schedule. Corporations using the combined income method must use Schedule K-121S.
- Carrying over the payroll percentage when using the elective two-factor formula. The apportionment schedule says not to carry this percentage to page 2.
- Entering an invalid credit forward. Line 46 is for an original return only and cannot exceed the total of lines 33, 34, and 35.
Questions people ask
How do I indicate an entity-level tax election?
Mark box N to elect to be subject to tax at the entity level. Box O is for an entity electing entity-level taxation that also wishes to tax 100% of the income for Kansas residents.
What tax rate appears on the 2025 form for an electing pass-through entity?
Line 32 calculates the tax as 5.58% of line 31, the total taxable income for electing partners.
Can I request a refund or apply an overpayment to next year?
Yes. Line 45 lets you enter the portion of the overpayment you want refunded. On an original return, line 46 lets you apply an amount to 2026 estimated tax, limited to the total of lines 33, 34, and 35.
How do I identify an amended return?
Mark the box labeled “IF THIS IS AN AMENDED RETURN.”
Can I authorize the department to discuss the return with my preparer?
Yes. The form includes an authorization allowing the Director of Taxation or the Director’s designee to discuss your return and enclosures with your preparer.