Interest on unpaid invoices in Hawaii: 10% a year if no rate was agreed; the most you can set depends on the deal

Hawaii's rate when no rate was agreed

10% a year. 10% a year when no written contract fixes a different rate; on an open account it runs after 60 days from the last item or transaction.

• “When there is no express written contract fixing a different rate of interest, interest shall be allowed at the rate of ten per cent a year” — Haw. Rev. Stat. § 478-2 Legal rate; computation, read November 6, 2026
• “For money upon an open account, after sixty days from the date of the last item or transaction.” — Haw. Rev. Stat. § 478-2(4), read November 6, 2026

The most you can set in Hawaii

For a homeowner: See the state's words below.

For a business customer: Any rate agreed in writing that is not otherwise prohibited by law. Applies to transactions other than consumer credit, home business loans and credit cards.

• “It shall in no case be deemed unlawful, with respect to any consumer credit transaction (except a credit card agreement) and any home business loan to stipulate by written contract, for any rate of simple interest not exceeding one per cent per month or twelve per cent a year” — Haw. Rev. Stat. § 478-4(a) Rate by written contract, read November 6, 2026
• “Credit extended to a natural person primarily for a personal, family, or household purpose” — Haw. Rev. Stat. § 478-1 Definitions ("Consumer credit"), read November 6, 2026
• “With respect to any transaction other than a consumer credit transaction, a home business loan, or a credit card agreement, it shall be lawful to stipulate by written contract for any rate of interest not otherwise prohibited by law.” — Haw. Rev. Stat. § 478-4(c) Rate by written contract, read November 6, 2026

Late fees in Hawaii

What the text says: It depends: see Haw. Rev. Stat. § 476-9. Credit sale contracts: late charge only if the contract provides for it, on an installment at least 10 days in default, max the lesser of $50 or 5% of the installment, once per installment, with written notice before the next payment is due. Credit sales of goods and/or services (services include work and labor, repairs and improvements) to natural persons, not primarily for business purposes, paid with a finance charge or in more than four installments. A credit sale contract means payment over a period of time subject to a finance charge, or under a written agreement in more than four installments not including a down payment.

• “The holder of a credit sale contract, including any financial services loan company, may, if the contract so provides, collect a late charge on each installment in default for a period not less than ten days in an amount not in excess of $50 or five per cent of each delinquent installment, or portion thereof which remains unpaid on the due date agreed upon in the contract whichever is less, and the late charge shall not be assessed more than once for the same delinquent installment.” — Haw. Rev. Stat. § 476-9 Late charges; court costs; attorney's fees, read November 6, 2026
• “either: (1) By payment thereof over a period of time subject to a finance charge; or (2) Pursuant to a written agreement, subject to payment in more than four installments not including a down payment” — Haw. Rev. Stat. § 476-1 Definitions ("Credit sale contract"), read November 6, 2026

Does Hawaii want it agreed in advance?

Agreed in advance: yes, in the cases below. For credit sale contracts the late charge is allowed only 'if the contract so provides'; for interest, the legal rate applies 'when there is no express written contract fixing a different rate', and higher contract rates must be stipulated by written contract (§ 478-4).

• “may, if the contract so provides, collect a late charge” — Haw. Rev. Stat. § 476-9, read November 6, 2026
• “The seller or other holder shall give the buyer written notice of the assessment of the late charges prior to the due date of the next contractual payment.” — Haw. Rev. Stat. § 476-9 (notice), read November 6, 2026

Homeowners and businesses in Hawaii

Consumer credit transactions are capped at 12% a year by contract (business: any rate not otherwise prohibited); the credit-sale late-charge cap ($50 / 5%) excludes sales primarily for a business, commercial or agricultural purpose.

• “Primarily for a business, commercial, or agricultural purpose” — Haw. Rev. Stat. § 476-1 Definitions ("Credit sale" exceptions), read November 6, 2026

Prompt payment on private construction in Hawaii

What the text says: 1.5% a month on the unpaid amount from the date payment is due (contractor → subcontractor; due 10 days after the invoice or after the owner pays the contractor, whichever is later). Contractor-to-subcontractor payments under the contractors chapter. It does not apply if the delay in payment is due to a bona fide dispute between the contractor and the subcontractor. The subcontractor shall be entitled to receive this interest from the contractor.

• “The subcontractor shall be entitled to receive interest on the unpaid amount at the rate of one and one-half per cent per month from the date payment is due; provided that this section shall not apply if the delay in payment is due to a bona fide dispute between the contractor and the subcontractor concerning the goods and services contracted for.” — Haw. Rev. Stat. § 444-25 Payment for goods and services, read November 6, 2026

Work out a late charge in Hawaii

Starts at Hawaii's 10%, the rate when none was agreed, not a maximum.

What was not checked for Hawaii

• Hawaii's § 478-1, as read, defines "consumer credit" but not "consumer credit transaction" on its own.

Check Hawaii's own text

Before you charge: read Haw. Rev. Stat. § 478-2 Legal rate; computation and the other Hawaii texts quoted on this page, or ask a lawyer. As of November 6, 2026.

This is a plain-words summary of each state's own laws as of November 6, 2026, not legal advice. Rules have exceptions. Check the state's own text, linked on every state's page, or a lawyer before you charge a late fee or interest.

Compare Hawaii with every state's answer.

Official sources for Hawaii

• Haw. Rev. Stat. § 478-2 Legal rate; computation — read November 6, 2026
• Haw. Rev. Stat. § 478-4(a) Rate by written contract — read November 6, 2026
• Haw. Rev. Stat. § 478-1 Definitions ("Consumer credit") — read November 6, 2026
• Haw. Rev. Stat. § 476-9 Late charges; court costs; attorney's fees — read November 6, 2026
• Haw. Rev. Stat. § 476-1 Definitions ("Credit sale contract") — read November 6, 2026
• Haw. Rev. Stat. § 444-25 Payment for goods and services — read November 6, 2026

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