California Late Fee Calculator
Calculate late fees and interest on overdue invoices in California — pre-set to the state's 10% statutory default rate.
Late fee rules in California
Statutory interest rate
10% per year on breach of contract where the contract is silent (contracts entered after Jan 1, 1986); 7% constitutional default for non-contract obligations; judgment rate 10%.
Cal. Civ. Code § 3289(b); Cal. Const. art. XV § 1; Code Civ. Proc. § 685.010
Can you charge more? (contract & caps)
No statutory cap on B2B invoice late fees — the contract controls subject to the liquidated-damages reasonableness test of Civ. Code § 1671. Ordinary trade-credit late charges between businesses are generally analyzed as liquidated damages rather than usury.
Prompt payment rules
Private construction prompt-pay rules impose a 2%-per-month penalty on wrongfully withheld progress payments (Civ. Code §§ 8800, 8802; Bus. & Prof. Code § 7108.5), and the California Prompt Payment Act (Gov. Code § 927 et seq.) penalizes late payments by state agencies on a 45-day clock.
Worth knowing
California runs two default prejudgment rates side by side — 10% for breach of contract but only 7% for non-contractual obligations — so the same unpaid work can accrue at different rates depending on the legal theory.
This page is general information, not legal advice. Statutory rates change — some reset annually or quarterly — and how they apply depends on your contract and situation. Verify current rates against the cited statutes or consult a lawyer before charging interest.
Free Download
Late Payment Policy Template
Complete policy document with grace periods, fee schedules, escalation timelines, and payment plan options.
Download free