Reference · Maine · 2026
Maine late payment interest rate
When your contract sets no rate, the Maine figure for interest on an overdue B2B invoice is 1-yr T-bill + 3pp, under 14 M.R.S. § 1602-B.
Prejudgment interest in civil actions; if the contract or note states a rate, that rate applies. No general out-of-court legal rate.
- Rate
- 1-yr T-bill + 3pp
- Statute
- 14 M.R.S. § 1602-B
- Type
- Floats: resets on a schedule. The figure is the published 2026 (or current-quarter) value.
- Source
- legislature.maine.gov · verified July 9, 2026
Work out the interest on your invoice
Maine publishes no fixed rate outside court, so this starts at 18% (1.5% a month), the common contract rate. Enter your contract's rate.
Interest you can claim
$295.89
$10,295.89 with the invoice · $4.93 a day
The ceiling
How high can a late fee go in Maine?
Your contract decides. The rate above only applies when your terms are silent. Between businesses, an agreed late-interest rate or late fee replaces it, within two limits: the state's ceiling on agreed rates, and the rule that a late fee must compensate you rather than punish the customer.
Maine's ceiling on an agreed rate wasn't part of our verified research, so check the state's usury law, or ask a lawyer licensed in Maine, before writing the common 1.5%-a-month (18%) rate into your terms.
Late payment wording for a Maine invoice
On your invoice
Payment is due by the date shown on this invoice. Late payments are subject to interest at the legal rate under 14 M.R.S. § 1602-B (1-yr T-bill + 3pp).
This restates what Maine law applies when your contract is silent. If your contract sets a rate, quote that instead. The wording doesn't say when interest starts, because that differs by state; the note at the top of this page covers it where Maine law sets it.
How Maine compares
Maine is one of 4 states with no rate that applies on its own, along with New Mexico, South Dakota and Tennessee. Elsewhere the middle of the range is 8%.
Interest is the fallback. Getting paid on time is the plan.
DueTrail turns overdue invoices into managed cases with reviewable reminders and recorded promises to pay, so invoices get settled before anyone reaches for 14 M.R.S. § 1602-B.