Updated October 12, 2026. Quick answer: Up to 15% a year by stipulation in the note, with business and agricultural loans outside the limit, and 10% a year when no rate is agreed (K.S.A. 16-207 and 16-201).
Kansas promissory note at a glance
| Item | What the documents say |
|---|---|
| Maximum interest rate on a private loan | 15% a year; business and agricultural loans, consumer credit code transactions and certain other loans are outside the limit |
| Rate if the note names none | 10% a year on money after it becomes due, when no other rate is agreed |
| Penalty for charging too much | Contracting for a greater rate forfeits the excess interest plus an equal sum from the principal and lawful interest, and the borrower also recovers a reasonable attorney fee (not applicable to Kansas mortgage business act or consumer credit code transactions) |
What Kansas law says about interest
Kansas lets the parties to a promissory note stipulate interest at a rate not to exceed 15% per annum unless otherwise specifically authorized by law.
When no other rate of interest is agreed upon, creditors are allowed interest at 10% per annum on money after it becomes due.
The 15% limit does not apply to business or agricultural transactions (loans made primarily for purposes other than personal, family or household purposes), consumer credit code transactions and certain other loans; a person contracting for a greater rate forfeits the excess interest plus an equal sum from the principal and lawful interest.
The sources in their own words
- Interest limit: “at a rate not to exceed 15% per annum” (K.S.A. 16-207 Contract rate; penalties; contracting for interest in excess of limitation).
- Rate when none is agreed: “10% per annum when no other rate of interest is agreed upon” (K.S.A. 16-201 Legal rate of interest).
- Exemption or penalty: “a business or agricultural transaction” (K.S.A. 16-207 Contract rate; penalties; contracting for interest in excess of limitation).
- Exemption or penalty: “shall forfeit all interest so contracted for in excess” (K.S.A. 16-207 Contract rate; penalties; contracting for interest in excess of limitation).
- Time limit to sue: “must be commenced within six years after the due date” (K.S.A. 84-3-118 Statute of limitations).
- Time limit to sue: “An action upon any agreement, contract or promise in writing” (K.S.A. 60-511 Actions limited to five years).
If you’re ready to put it in writing
This is free to browse and there is no obligation to buy anything. LawDepot builds a state-specific promissory note through a question-and-answer form.
Build a promissory note at LawDepot
LawDepot pays us a commission if you buy through this link. It costs you nothing extra. We are not a law firm and this is not legal advice. Affiliate Disclosure.
Signing the note: signature, witness, notary
Under Kansas UCC 3-401 a person is not liable on an instrument unless the person signed it or an authorized agent signed for them, and a signature may be any word, mark or symbol adopted to authenticate a writing. A note is signed by the person who promises to pay.
None of the sections read for Kansas requires a witness or a notary for the note itself. A note secured by real property is a separate question; see what an intra-family mortgage requires.
How long a lender has to sue
Kansas gives six years after the due date to sue on a note payable at a definite time (K.S.A. 84-3-118), and five years on other written agreements (K.S.A. 60-511).
A worked example: a $15,000 note
Suppose a relative lends you $15,000 and you sign a note for 5 years at 8% a year, paid monthly. With r = 8%/12 and n = 60 months, the level payment is principal times r divided by (1 minus (1 + r) to the power of negative n): $304.15 a month, computed here from these assumed inputs, not quoted. Over the 60 payments that is $18,249.00 in total, of which $3,249.00 is interest.
The 8% rate sits inside the Kansas limit in the table above, which is why it was chosen. The federal side of a loan between relatives is covered at family loan minimum interest rate and AFR rates by month.
A loan or a gift?
A loan that may never be repaid is taxed differently; see family loan vs gift, forgiving a family loan and gift tax by state.
What the documents do not say
- Which of the two time limits governs a particular note is a legal question the documents read do not settle.
- Silence on a witness or notary in the sections read is not proof that no other Kansas law requires one.
Common mistakes
- Charging more than the limit in Kansas, which the table gives as 15% (business and agricultural loans outside), forfeits all the excess interest plus an equal sum deducted from principal and lawful interest, and the borrower also recovers a reasonable attorney fee (16-207(d)).
- Leaving the rate out: when no other rate is agreed, Kansas allows 10% a year on money after it becomes due (16-201), and it is rarely what the parties meant.
- Waiting too long to enforce: Kansas allows 6 years (note); 5 years (other written contract) to sue on a written note.
Related: promissory notes by state, promissory note requirements, family loan minimum interest rate, and gift tax by state.
Sources
- K.S.A. 16-207 Contract rate; penalties; contracting for interest in excess of limitation: https://www.ksrevisor.gov/statutes/chapters/ch16/016_002_0007.html
- K.S.A. 16-201 Legal rate of interest: https://www.ksrevisor.gov/statutes/chapters/ch16/016_002_0001.html
- K.S.A. 84-3-118 Statute of limitations: https://www.ksrevisor.gov/statutes/chapters/ch84/084_003_0118.html
- K.S.A. 60-511 Actions limited to five years: https://www.ksrevisor.gov/statutes/chapters/ch60/060_005_0011.html
- K.S.A. 84-3-401 Signature: https://www.ksrevisor.gov/statutes/chapters/ch84/084_003_0401.html
Sources: the primary documents linked above, read on October 12, 2026. General information, not legal or tax advice. Statutes change and courts read them, so confirm anything consequential with a lawyer licensed in your state.