An IOU is the smallest legally meaningful piece of paper. It says one thing — 'I owe you' — and that one thing is enough to win a small-claims case if it ever comes to that.
Who this pack is for
You're loaning a small amount of money — under $5,000, no interest, due by a specific date — to someone you trust but want a paper trail with anyway. Maybe a friend needs help making rent and will pay you back next paycheck. Maybe a family member needs a bridge until a tax refund clears. Maybe you split a vacation expense and your travel partner will reimburse later. You don't want the formality of a promissory note with interest schedules and default clauses; you want a one-page acknowledgment that the money is owed and when it's due.
When to use it
Sign the IOU at the moment of the loan — both parties present, both signing. The borrower writes (or you write and they sign) acknowledging the amount, the date, and when it's due. For amounts under $1,000 between close family or friends, an IOU is appropriate. For amounts $1,000+, with interest, with a payment schedule, or where the relationship is professional rather than personal, use the promissory note instead — its enforcement language is stronger. For amounts over $5,000–$10,000, even between friends, the promissory note is worth the extra five minutes.
What it doesn't cover
The IOU is intentionally minimal: amount, due date, signature. It does not include interest (use a promissory note for that), late fees, default acceleration, attorney-fee recovery, or any security interest. It does not work well for installment payments — the IOU contemplates a single lump-sum repayment by the due date. If the borrower can't pay in full by the due date, you can renegotiate by signing a new IOU or a payment plan agreement, but the original IOU doesn't have a built-in workout mechanism. It does not address tax treatment of forgiven debt — if you forgive an IOU above $18,000 (the 2025 annual gift tax exclusion), gift-tax rules apply.
Common questions
Pike provides plain-language legal information, not legal advice. State and local rules change. If money, custody, or your housing is on the line, talk to a licensed attorney or your local legal aid office.