1. The interest of personal loan is calculated as follows:

(1) If the loan contract between natural persons does not stipulate or is unclear about the payment of interest, it shall be regarded as not paying interest;

(2) The agreed interest rate for personal loans may be appropriately higher than the bank interest rate, but it shall not exceed four times the bank interest rate for similar loans. The excess part is not protected by law, and the interest within four times is legal interest;

(3) The lender shall not include interest in the principal to seek high profits;

(4) If the borrower repays the loan in advance, unless otherwise agreed by the parties, the interest shall be calculated according to the actual loan period.

2. Legal basis: Article 680th of the Civil Code of People's Republic of China (PRC).

It is forbidden to lend at high interest, and the interest rate of borrowing shall not violate the relevant provisions of the state.

If there is no agreement on the payment of interest in the loan contract, it shall be deemed that there is no interest.

If the loan contract does not specify the method of interest payment, and the parties cannot reach a supplementary agreement, the interest shall be determined according to the local or the parties' trading methods, trading habits, market interest rates and other factors; Loans between natural persons are regarded as having no interest.

Second, how to deal with private lending interest disputes

The ways to deal with disputes over private lending interest are as follows:

1. If there is a dispute between the borrower and the lender about whether there is an agreed interest rate and it cannot be proved, the interest can be calculated by referring to the interest rate of similar loans from banks; If there is a dispute between the borrower and the borrower over the agreed interest rate and it is impossible to prove it, the interest may be calculated with reference to the legal provisions;

2. For interest-free loans between citizens, there is an agreed repayment period, and the borrower fails to repay on time, and the lender requires the borrower to pay overdue interest, or there is no agreed repayment period, and the borrower still fails to repay after being urged by the lender, the lender shall allow him to pay the interest after being urged, and the interest can be calculated with reference to the interest rate of similar loans of banks.