Can I sue someone for not paying back an IOU?
Yes. An IOU is one of the strongest types of loan evidence. A signed IOU is written proof of the debt: amount, parties, often the date and any terms. Most state laws treat IOUs as enforceable contracts (also called 'promissory notes'). The case is usually straightforward at the hearing because the borrower's own writing establishes the debt. Filing deadlines are longer for written IOUs (4 to 6 years in most states, sometimes 10).
What makes an IOU enforceable?
Four elements. Most signed IOUs include enough to enforce.
How much can you claim?
IOU amount plus pre-judgment interest plus filing fees.
Illustrative ranges based on statute. Your actual recovery depends on facts, evidence, and the judge.
IOU principal
The amount stated in the IOU. The signed document is decisive evidence at the hearing.
Pre-judgment interest
Specified in the IOU or state legal rate (7 to 10 percent per year typical). Running from the agreed repayment date or first demand.
Filing fees, post-judgment interest
Filing fee, service-of-process cost, post-judgment interest accruing until paid.
$4,000 IOU plus 3 years of pre-judgment interest at 10 percent, plus filing fee.
Send a demand letter first.
Demand letters with the IOU attached produce settlement in most cases. The borrower knows the IOU is decisive evidence and has limited defenses.
Send a Demand Letter.
- Copy of the signed IOU
- Date of the IOU and any agreed repayment date
- Any prior demands or partial payments
- Pre-judgment interest calculation
- A 14-day deadline before you file
- Sent certified mail with copy of IOU attached
1424 Maple Lane, Phoenix, AZ 85003
On June 14, 2023, you signed an IOU for $4,000 (copy attached). The IOU specified repayment within 12 months. Three years and four months have passed without any payment. The IOU is enforceable as a written promissory note.
I demand within fourteen (14) days:
- Payment of $4,000 in IOU principal;
- Pre-judgment interest at 10 percent per year for 3 years ($1,200).
“The letter alone got them to settle in under two weeks.”
How to file an IOU case.
Four steps. The signed IOU is the case.
Original signed document is best. A clear copy works in most courts. If the original is lost, look for any photograph, scan, or secondary record (bank statement reflecting deposit of the loan).
Attach a copy of the IOU. Certified-mail receipt creates the formal record.
If demand fails, file. Filing fees usually run $30 to $100. Bring the original IOU to the hearing.
Lead with the IOU. The borrower's signature on the document is decisive. Hearings usually run 10 to 15 minutes.
What evidence do you need to sue on an IOU?
The IOU itself is the case. Other evidence is supporting.
Common borrower defenses, with rebuttals.
Three arguments cover most IOU cases. Few succeed.
Keep it simple. Organized records, clear timelines, and solid evidence are your best defense.
How much do lenders actually recover?
IOU cases produce predictable, full recoveries with strong documentation.
IOU rules, by state.
Top 10 states by case volume, highlighted in red. Each row shows that state's deadline to sue and statutory penalty for this claim.
What if your case is over your state’s cap?
Small claims caps vary state to state. If your claim is larger, you have two options.
Stay in small claims and forfeit anything above your state's cap. Fast, cheap, no lawyer. Most plaintiffs in this situation pick this.
Pursue the full amount in regular civil court. Slower, costlier, lawyer recommended.
What are the alternatives to small claims?
IOU cases have strong demand-letter outcomes. Court is the backup.
When it fits: any signed IOU. The borrower knows the IOU is decisive evidence. Most pay within 14 days.
Tradeoff: no enforcement if borrower ignores.
When it fits: you want to recover but maintain the relationship. Mediation can negotiate payment plans.
Tradeoff: no enforcement; only effective if borrower participates.
When it fits: demand letter ignored. Damages within your state's cap.
Tradeoff: 30 to 90 day timeline. Strong cases at the hearing.
Enforce the IOU.
Demand letters with the IOU attached produce settlement in most cases. Our generator builds yours in under two minutes.
Illustrative. Larger IOUs push to small-claims cap.
This page is general legal information about personal loan disputes, not legal advice. CivilCase is not a law firm and does not represent you. Consult a licensed attorney in your state for advice about your specific situation.
IOU questions.
The questions lenders actually ask before filing.
Is a handwritten IOU enforceable?
Yes. Most state laws enforce handwritten IOUs as written contracts. The signature plus the dollar amount plus the parties named are usually enough. Even an IOU on a napkin counts if the elements are present.
What if the IOU doesn't specify a repayment date?
Without a specified date, the loan is 'on demand': payable when the lender asks. The demand letter triggers the legal obligation. Statute of limitations starts running on the demand date, not the IOU date.
What about an electronic IOU (text or email)?
Most states recognize electronic signatures and writings as enforceable contracts. A text or email saying 'I owe you $4,000, will pay back by June' from the borrower is essentially an electronic IOU. UCC and state e-sign laws enforce these.
Should I include interest in the IOU?
Yes, especially for loans over a year. Interest specified in the IOU is enforceable up to state usury limits. Without specified interest, you can claim the state pre-judgment rate (7 to 10 percent typical), but specifying in advance is cleaner.
What if the borrower disputes my signature on the IOU?
The borrower's signature is what matters; yours is rarely disputed. If the borrower challenges authenticity, the court can compare to known signatures. Bank deposits and follow-up texts also corroborate.
How long do I have to sue on an IOU?
Written contracts: 4 to 6 years in most states (some up to 10). The IOU is a written contract. Statute starts on the agreed repayment date or first demand. Move within the deadline.
Can I charge interest above what's in the IOU?
No. The IOU controls. If the IOU is silent on interest, you can claim pre-judgment interest at the state legal rate but not contractual interest higher than what was agreed. State usury limits also cap contractual interest.