Maine Late Fee Calculator
Work out interest on an overdue B2B invoice under Maine law. When the contract is silent, the default is variable — the currently published figure, the official page that sets it, the written-contract cap, and the statute are all on this page.
When the contract is silent: 1-year U.S. Treasury bill rate +3 pts (prejudgment; T-bill +6 pts after judgment). The rate is fixed for the whole year at the Fed's weekly average 1-year constant maturity Treasury yield for the last full week of the PRIOR calendar year (not the current week's H.15 figure). For 2026 the anchor is the week ending December 26, 2025, whose weekly average was 3.51%, so the 2026 figures are 6.51% before judgment and 9.51% after.
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 Maine's statute (14 M.R.S. §§ 1602-B, 1602-C; 9-A M.R.S. § 1-202(1)) for you.
What Maine law actually says
prejudgment interest is allowed at the one-year United States Treasury bill rate plus 3%. [...] the weekly average one-year constant maturity Treasury yield, as published by the Board of Governors of the Federal Reserve System, for the last full week of the calendar year immediately prior to the year in which prejudgment interest begins to accrue.
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 Maine — written B2B contracts
No statutory cap
No general cap on business/commercial credit; the Consumer Credit Code excludes business-purpose extensions and the old usury statute is repealed. Set the rate in writing.
Basis: 9-A M.R.S. § 1-202(1). 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 Maine'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
Maine'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.
Maine late fee FAQ
Can I charge late fees on overdue invoices in Maine?
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: Variable; currently published figure: 6.51% (2026). When the contract is silent: 1-year U.S. Treasury bill rate +3 pts (prejudgment; T-bill +6 pts after judgment). The rate is fixed for the whole year at the Fed's weekly average 1-year constant maturity Treasury yield for the last full week of the PRIOR calendar year (not the current week's H.15 figure). For 2026 the anchor is the week ending December 26, 2025, whose weekly average was 3.51%, so the 2026 figures are 6.51% before judgment and 9.51% after. Statute: 14 M.R.S. §§ 1602-B, 1602-C; 9-A M.R.S. § 1-202(1), verified 2026-08-19. Consumer and rent debts follow separate laws.
What is the maximum late fee I can charge in Maine?
For a written B2B contract: No general cap for business/commercial credit — Maine's Consumer Credit Code excludes business-purpose extensions of credit. Basis: 9-A M.R.S. § 1-202(1). 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 Maine?
Variable — When the contract is silent: 1-year U.S. Treasury bill rate +3 pts (prejudgment; T-bill +6 pts after judgment). The rate is fixed for the whole year at the Fed's weekly average 1-year constant maturity Treasury yield for the last full week of the PRIOR calendar year (not the current week's H.15 figure). For 2026 the anchor is the week ending December 26, 2025, whose weekly average was 3.51%, so the 2026 figures are 6.51% before judgment and 9.51% after. Currently published figure: 6.51% (2026). Confirm the applicable figure via the official page linked on this page before relying on it. Statute: 14 M.R.S. §§ 1602-B, 1602-C; 9-A M.R.S. § 1-202(1).
Does this cover rent, apartment, or consumer late fees in Maine?
No. This page covers business-to-business invoices only. Residential rent late fees are governed by Maine'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 — Maine's row was last verified 2026-08-19. 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 Maine'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.