Demand Letter Generator for Unpaid Invoices
Turn an overdue invoice into a formal, dated demand for payment — with the interest computed for you and, if no rate was ever agreed, your state's statutory default rate cited to the controlling statute (from the same verified 51-jurisdiction table as our late fee calculator). Everything runs in your browser; nothing you type is sent anywhere.
Not legal advice. This assembles a letter from your inputs and public statutes — it is general information. For significant or disputed amounts, have a licensed attorney review before sending.
Your demand letter
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Before you send: read every line — you are responsible for the letter's contents. Verify the cited statute against the official source in the state table, and keep a copy of the letter, the invoice, and your delivery evidence together. Not legal advice.
How the interest is computed
Simple interest: interest = amount × (APR ÷ 365) × days overdue
Days overdue are counted from the invoice due date to today. The same formula (and the same verified state table) powers our late fee calculator — start there if you only need the number, come here when you need the letter.
Where the statutory rates come from
When you pick “use my state's statutory default”, the rate, the statute citation, and (optionally) the verbatim statutory text come from our 51-jurisdiction reference table — every row individually verified against the primary source with the verification date shown, and re-checked on a published schedule (changelog). States that set the rate by formula or periodic order link the official current-rate page instead of a frozen number.
Demand Letter FAQ
Is this letter legal advice?
No. This tool assembles a letter from your inputs plus the statutory citations in our verified state table. It is general information, not legal advice, and no attorney-client relationship is created. For significant amounts, disputed debts, or anything already in litigation, have a licensed attorney in your state review before sending.
How is the interest figure calculated?
Simple interest: amount × (annual rate ÷ 365) × days overdue — the same formula as our late fee calculator. If your contract or invoice states a rate, use that rate. If nothing was agreed, most US states supply a statutory default rate; pick your state and the letter cites the controlling statute for it.
Can I demand interest if my contract never mentioned late fees?
In most US states, yes — a statutory default interest rate applies to overdue commercial debts even when the contract is silent, and that is exactly the rate this tool inserts, with the statute cited. The details (when interest starts, what rate) vary by state: check your state's row in our late fee table, and verify against the linked official source.
How should I send a demand letter?
Common practice is to send it in a way you can later prove: email with delivery/read confirmation, plus a mailed copy via a tracked or certified service where available. Keep a copy of the letter, the original invoice, and the delivery evidence together. If the deadline passes without payment, your options depend on the amount and your jurisdiction — small-claims court thresholds and procedures vary.