Oklahoma Late Fee Calculator
Work out interest on an overdue B2B invoice under Oklahoma law. The legal default rate — what applies when the contract is silent — is 6%, and the statute is quoted verbatim below. All math runs locally in your browser.
Legal rate absent a contract rate; liquidated sums earn interest from the day the right to recover vested.
Late fee breakdown
- Interest owed
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- Daily rate
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- Total (invoice + interest)
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Still unpaid? Generate a formal demand letter — it computes the interest and cites Oklahoma's statute (15 O.S. § 266; Okla. Const. art. XIV, § 2) for you.
What Oklahoma law actually says
[...] in the absence of legislation fixing maximum rates of interest, all contracts for a greater rate of interest than ten percent(10%) per annum shall be deemed usurious; provided, further, that in contracts where no rate of interest is agreed upon, the rate shall not exceed six percent (6%) per annum.
Quoted verbatim from the linked official source — not our paraphrase. How we source and re-check every row is documented in the data methodology.
Maximum late fee in Oklahoma — written B2B contracts
Hard cap 10% (constitutional).
10%/yr constitutional ceiling is the residual rule for ordinary B2B contracts; no blanket business exemption. Higher rates need a specific statute (licensed/consumer regimes).
Basis: Okla. Const. art. XIV §2; 15 O.S. §266. Compare all 51 jurisdictions on the full state table and the cap-regime map.
B2B invoices only — not rent, not consumer debt
Everything on this page is about business-to-business invoices. Residential rent late fees live in Oklahoma's landlord-tenant law and consumer credit has separate, stricter rules — two different bodies of law. The distinction is explained in B2B invoice late fees vs. residential rent.
Use this data
Oklahoma's row — rate, cap, citation, verbatim quote, verification date — is part of our open 51-jurisdiction dataset: CSV · JSON (CC BY 4.0, cite myinvoicetemplate.com). Set late-fee terms on your next invoice with the free invoice generator, or state them clearly using the wording guidance in the payment terms guide.
Oklahoma late fee FAQ
Can I charge late fees on overdue invoices in Oklahoma?
Yes — on business-to-business invoices. If your contract or invoice states a late-fee rate, that rate governs (subject to the cap rules below). If nothing was agreed: 6%. Legal rate absent a contract rate; liquidated sums earn interest from the day the right to recover vested. Statute: 15 O.S. § 266; Okla. Const. art. XIV, § 2, verified 2026-08-21. Consumer and rent debts follow separate laws.
What is the maximum late fee I can charge in Oklahoma?
For a written B2B contract: 10% constitutional ceiling as the residual rule; statutes authorize higher rates for various licensed/consumer lending regimes. Basis: Okla. Const. art. XIV §2; 15 O.S. §266. The full cap analysis is in the section above; this covers business-to-business deals only — consumer credit has stricter separate caps.
What interest applies if my contract doesn't mention late fees in Oklahoma?
The statutory default rate of 6%. Legal rate absent a contract rate; liquidated sums earn interest from the day the right to recover vested. Statute: 15 O.S. § 266; Okla. Const. art. XIV, § 2 (verbatim quote on this page, verified 2026-08-21).
Does this cover rent, apartment, or consumer late fees in Oklahoma?
No. This page covers business-to-business invoices only. Residential rent late fees are governed by Oklahoma's landlord-tenant law, and consumer credit for personal, family, or household purposes has its own stricter caps and disclosure rules. Those are different statutes than the commercial-interest law cited here.
Where does this data come from, and when was it verified?
Every figure on this page comes from our 51-jurisdiction dataset: each row researched against the controlling statute or the state's official current-rate page, independently re-checked, and stamped with its own verification date — Oklahoma's row was last verified 2026-08-21. The operative legal text is quoted verbatim on this page with a link to the official source, the methodology is public, every verification pass is logged in the changelog, and the full dataset is downloadable (CC BY 4.0).
Not legal advice. This page summarizes Oklahoma's commercial-interest statute for general information, with the verification date shown above — it tells you when we last confirmed the figures, not that they are still current today. Statutes change and courts interpret them; verify the cited statute at the official source, or ask a licensed attorney in your state, before charging or demanding interest.