You will need
  • calculator
  • pencil
  • - a sheet of paper
In order to calculate the delay, use simple math. Let's say that every month we pay on the loan is 5 000 rubles. However, we understand that in the current month to pay the loan on time can not.
Read the credit agreement. Suppose it is specified that the penalty is 0.5% for each day of delay. Thus, the next day after the payment deadline we will still owe the Bank (5000 × 0.5%) was 25 rubles. That is, for repayment of arrears we have to pay for 5025 rubles.
Suppose we know that paying late will be 5 days after the payment date. To calculate delay in this case.
Debt after 1 day of delay is 5025 rubles. Following the 0.5% interest will be charged on this amount.

Thus, debt at the end of 2 days of delay will be (5025 × 0,5% + 5025) 5050,13 rubles.
Similarly, to calculate the delay should be for the rest of the day.
At the end of 3 days (5050,13 × 0,5% + 5050,13) - 5075,38 rubles.

At the end of 4 days (5075,38 × 0,5% + 5075,38) - 5100,76 rubles.

At the end of 5 days (5100,76 × 0,5% + 5100,76) - 5126,26 rubles.
Even if we pay the loan on the morning of 5 day, to calculate the delay should be for 5 whole days, as the funds are debited from the accounts happens 1 time a day, usually late in the evening.
Now you will be able to correctly calculate the delay and repay the debt with accuracy to the penny.