California Late Fee Calculator
Work out interest on an overdue B2B invoice under California 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.
Default on contract debts after breach when the contract is silent; runs from the date a fixed sum became due.
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 California's statute (Cal. Civ. Code § 3289(b); Cal. Const. art. XV, § 1) for you.
What California law actually says
(b) If a contract entered into after January 1, 1986, does not stipulate a legal rate of interest, the obligation shall bear interest at a rate of 10 percent per annum after a breach.
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 California — written B2B contracts
No statutory cap
Usury reaches only loans/forbearance, not bona fide trade credit. A finance charge on a real B2B invoice is unconstrained; set the rate by written agreement.
Basis: Cal. Const. art. XV §1; Civ. Code §3289. 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 California'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
California'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.
California late fee FAQ
Can I charge late fees on overdue invoices in California?
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%. Default on contract debts after breach when the contract is silent; runs from the date a fixed sum became due. Statute: Cal. Civ. Code § 3289(b); Cal. Const. art. XV, § 1, verified 2026-08-19. Consumer and rent debts follow separate laws.
What is the maximum late fee I can charge in California?
For a written B2B contract: Usury law reaches only loans/forbearance — not bona fide trade-credit terms. For true business loans: higher of 10% or FRBSF discount rate +5 pts, with broad exemptions (e.g. $300,000+ entity credit, licensed lenders). Basis: Cal. Const. art. XV §1; Civ. Code §3289. 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 California?
The statutory default rate of 10%. Default on contract debts after breach when the contract is silent; runs from the date a fixed sum became due. Statute: Cal. Civ. Code § 3289(b); Cal. Const. art. XV, § 1 (verbatim quote on this page, verified 2026-08-19).
Does this cover rent, apartment, or consumer late fees in California?
No. This page covers business-to-business invoices only. Residential rent late fees are governed by California'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 — California'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 California'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.