Late Payment Interest Calculator
Calculate overdue interest and penalty amounts for late payments and contract breaches.
Answer summary
Calculate overdue interest and penalty amounts for late payments and contract breaches.
- Primary sources: U.S. Code · United States Courts · USA.gov
🔎 Official sources
How to use Late Payment Interest Calculator well
This section is here to make the page more useful in real legal prep, not just more readable.
Who this page is for
People checking statutory or contractual late-payment exposure before sending a demand or negotiating payoff.
What this page does not decide
This page does not decide which rate governs, whether compounding is allowed, or whether interest is recoverable in court.
Verify before you rely on it
- the legal basis for interest: contract, statute, or judgment rule
- the start date that actually triggers accrual
- whether caps, simple-interest rules, or notice requirements apply locally
Common mistakes
- using a consumer rate for a commercial debt
- counting from the invoice date when the contract uses another trigger
- adding compound interest where only simple interest is allowed
Official source cross-check
Cross-check U.S. Code, United States Courts, and USA.gov before treating this page as a reliable planning reference.
Practical next step
Match your calculation to the governing contract or statute, then keep the worksheet with your demand letter or settlement file.
How to use this tool
Calculate overdue interest and penalty amounts for late payments and contract breaches.