For private loans with no agreed interest, the creditor cannot ask the debtor to pay interest when demanding repayment. When borrowing money, the repayment period is agreed, or although the repayment period is not agreed, but the creditor has urged the debtor to repay within a certain period of time, and still fails to repay within the time limit, the creditor may require the debtor to pay the interest on overdue repayment. Interest-free loans between citizens have an agreed repayment period, but if the borrower fails to repay on time, or fails to repay after being urged by the lender, if the lender requires the borrower to pay overdue interest, it shall be allowed.

legal ground

Article 26 of the Provisions on Several Issues Concerning the Application of Law in the Trial of Private Lending Cases

If the lender requests the borrower to pay interest at the interest rate agreed in the contract, the people's court shall support it, except that the interest rate agreed by both parties exceeds four times the quoted interest rate of the one-year loan market at the time of the establishment of the contract.

The "one-year loan market quotation rate" mentioned in the preceding paragraph refers to the one-year loan market quotation rate issued monthly by the National Interbank Funding Center authorized by the People's Bank of China from August 20, 20 19.