How to write a formal IOU
In daily life or business dealings, borrowing and lending is inevitable. In order to protect the rights and interests of both parties, it is crucial to sign a formal IOU. This article will introduce in detail the legal elements, writing format and precautions of IOUs, and provide structured data for reference.
1. Legal elements of IOUs

According to the Civil Code of the People's Republic of China, a valid IOU must contain the following core contents:
| elements | Description |
|---|---|
| Title | Clearly state the word "IOU". |
| Borrower information | Name, ID number, contact information, etc. |
| Lender information | Name, ID number, contact information, etc. |
| Borrowing amount | Uppercase and lowercase numbers must match. |
| Borrowing purpose | Indicate the purpose of the funds (not required but recommended). |
| repayment period | Specify specific dates or conditions. |
| interest agreement | If there is no interest, please write "no interest". |
| Signature and seal | Both parties sign and fingerprint, and stamp with official seal (if it is an organization). |
2. IOU standard template
The following are examples of common IOU formats:
| content | Example |
|---|---|
| Title | IOU |
| Text | Owe todayZhang San(ID number: XXX) RMBTen thousand yuan (¥10,000.00), used forDecorate the house, inJanuary 1, 2025Pay it off in advance with no interest during the period. Overdue payment, calculated on a daily basis0.05%Pay liquidated damages. |
| signature | Borrower:John Doe(Signed and fingerprinted) Date:May 10, 2024 |
3. Precautions
1.avoid ambiguity: Key information such as amount and date must be supplemented with uppercase Chinese characters.
2.Keep evidence: It is recommended to transfer via bank and note "borrowing" to avoid cash transactions.
3.legitimacy: The annual interest rate exceedsFour times LPR (about 15.4%)parts are not protected by law.
4.witness: Large-amount loans can be signed by a third-party witness.
4. Frequently Asked Questions
| question | answer |
|---|---|
| Are handwritten IOUs valid? | It is valid, but the writing must be clear and without alteration. |
| What should I do if the interest rate is not agreed upon? | It is regarded as an interest-free loan, but LPR interest can be claimed if it is overdue. |
| How long is the statute of limitations for IOU litigation? | Usually3 years, calculated from the due date of repayment. |
Through the above structured data and templates, you can quickly master the writing specifications of formal IOUs. It is recommended that both parties to the loan retain the original documents of the IOU and consult a professional lawyer if necessary to ensure their rights and interests.
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