Free tool
Late fee calculator
The fee your terms actually support, derived in front of you, with your state's statute cited alongside. If nothing was agreed, it says so rather than inventing a charge.
Before you charge it
Three checks that keep a fee defensible
- 1. The terms were agreed in advance. A fee announced after the fact is generally unenforceable. It belongs in your contract or accepted terms, restated on the invoice. See how to charge late fees and stay legal.
- 2. The rate clears your state's limits.Usury caps and the liquidated-damages doctrine both constrain agreed rates, and the limits differ sharply by state. The statute panel above shows your state's rules with citations; the full write-ups are in the late fee laws library.
- 3. You apply it consistently. A fee charged only when someone remembers is unfair and legally weaker. This is the part software should own: Duebay computes fees by rule and chases by sequence, with every action logged.
FAQ
Calculator questions
How is the late fee calculated?
From the terms agreed on your invoice, as simple (non-compounding) daily interest: balance x annualized rate / 365 x chargeable days, after any grace period. Flat fees are applied once. Every step is shown in the derivation so you can reproduce it by hand. Compounding is deliberately not offered; simple interest is the standard, defensible reading of an invoice late-fee clause.
What if no late-fee terms were agreed?
Then there is nothing to charge, and the calculator says so: a late fee generally must be agreed in advance to be enforceable. If you selected a state, it shows the state's statutory interest figure as a clearly-labelled reference, because that (not a retroactive fee) is usually the relevant fallback in a dispute.
Where do the statute numbers come from?
From our 50-state library, researched against official sources with citations, source URLs and a confidence grade per entry. States that set rates by formula (Florida, Ohio and others) show the formula and where the current figure is published. Anything unverified says "verify with counsel" instead of guessing.
Does my data leave the browser?
No. The engine is TypeScript loaded into this page and the computation runs client-side; there is no request carrying your figures, which you can confirm in your browser's network tab.
Is this legal advice?
No. It is arithmetic from your inputs plus general statutory information with citations. Statutes change and contracts vary; confirm with counsel before relying on a figure in a dispute.
Fees are the teeth. Sequences are the follow-through.
Duebay chases every overdue invoice with an escalating sequence and computes fees exactly like this, citation included.