Legal analysis: the standard of overdue penalty interest is as follows: 1, and the annual interest rate does not exceed 24%, which is legal and effective. If the interest rate agreed by both parties does not exceed the annual interest rate of 24%, and the lender requests the borrower to pay interest at the agreed interest rate, the people's court shall support it. 2, the annual interest rate of more than 24% to 36%, according to the wishes of the parties. Private lending with an annual interest rate of 24%~36% belongs to natural debt. The court will not protect the lawsuit, but the parties are willing to perform it automatically, and the court has no objection. The borrower cannot demand the repayment of the interest already paid. 3. The annual interest rate exceeds 36%, and some of them are invalid.

Legal basis: Article 29 of the Provisions of the Supreme People's Court on Several Issues Concerning the Application of Laws in the Trial of Private Lending Cases, the lender and the borrower have agreed on overdue interest rates, liquidated damages or other expenses. Lenders can choose to claim overdue interest, liquidated damages or other expenses, or both, but the people's court will not support the part that exceeds 4 times the listed interest rate of one-year loan market.