New Hampshire Late Fee Calculator
Work out interest on an overdue B2B invoice under New Hampshire law. The legal default rate — what applies when the contract is silent — is 10%, and the statute is quoted verbatim below. All math runs locally in your browser.
Rate recovered in litigation (pre- and post-judgment): 26-week T-bill discount rate +2 pts, set annually by the State Treasurer. A fixed 10% residual default applies to business transactions outside that context.
Late fee breakdown
- Interest owed
- —
- Daily rate
- —
- Total (invoice + interest)
- —
Still unpaid? Generate a formal demand letter — it computes the interest and cites New Hampshire's statute (RSA 336:1) for you.
What New Hampshire law actually says
I. The annual rate of interest in all business transactions in which interest is paid or secured, unless otherwise agreed upon in writing, shall equal 10 percent. No consumer credit transaction, as defined in RSA 358-K:1, V, shall be subject to this paragraph. If agreed upon in writing, interest on business transactions may include charging other than simple interest.
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 New Hampshire — written B2B contracts
No statutory cap
No numeric usury cap on business transactions agreed in writing; rate limits are reserved for consumer credit. Set the B2B rate in writing.
Basis: RSA 336:1, I. 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 New Hampshire'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
New Hampshire'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.
New Hampshire late fee FAQ
Can I charge late fees on overdue invoices in New Hampshire?
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: 10%. Rate recovered in litigation (pre- and post-judgment): 26-week T-bill discount rate +2 pts, set annually by the State Treasurer. A fixed 10% residual default applies to business transactions outside that context. Statute: RSA 336:1, verified 2026-08-21. Consumer and rent debts follow separate laws.
What is the maximum late fee I can charge in New Hampshire?
For a written B2B contract: No cap for business transactions agreed in writing (consumer credit is the only carve-out). Basis: RSA 336:1, I. 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 New Hampshire?
The statutory default rate of 10%. Rate recovered in litigation (pre- and post-judgment): 26-week T-bill discount rate +2 pts, set annually by the State Treasurer. A fixed 10% residual default applies to business transactions outside that context. Statute: RSA 336:1 (verbatim quote on this page, verified 2026-08-21).
Does this cover rent, apartment, or consumer late fees in New Hampshire?
No. This page covers business-to-business invoices only. Residential rent late fees are governed by New Hampshire'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 — New Hampshire'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 New Hampshire'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.