1. Article 21 of the Supreme People's Court's Interpretation on Several Issues Concerning the Application of the People's Republic of China (PRC) Contract Law stipulates that the debtor shall pay interest and expenses in addition to the principal debt. If the payment is insufficient to pay off all debts, and the parties have not agreed, the people's court shall pay off the debts in the following order.

(1) Expenses related to the realization of creditor's rights;

(2) interest;

(3) Principal debt.

Therefore, if there is no agreement on whether to pay the principal or interest first in private lending, how to determine the repayment order, then you should pay the interest first and then the principal.

2. Private lenders and borrowers should agree on the time of interest payment and the order of repayment of principal and interest in the contract to avoid disputes over whether to pay interest or principal due.

Article 675 of the Civil Code, the borrower shall repay the loan within the agreed time limit. If the term of the loan is not agreed or clearly agreed, and cannot be determined according to the provisions of Article 510 of this Law, the borrower may return it at any time; The lender may urge the borrower to repay the loan within a reasonable period of time.

Article 676 If the borrower fails to repay the loan within the agreed time limit, it shall pay the overdue interest in accordance with the agreement or the relevant provisions of the state.

Article 677 Where the borrower prepays the loan, unless otherwise agreed by the parties, the interest shall be calculated according to the actual loan period.