If you don't know how to calculate the pension, study existing on this question are articles and legal acts of the Russian legislation. It should be noted that the mandatory information to calculate the pension are the years of service, the salary for the position, the salary on a special rank and the percentage that will be added to the pension for years of service. At the moment the pension is calculated as a percentage.
So in 20 years it should preferential of 50% of the salary for the position and special rank. For each benefit year in accordance with the Russian legislation adds 3%. However, the pension cannot exceed 85% of the amount received. For example, the salary for the position was 12,000 rubles, the salary for a special rank 4000 rubles. The length of service is 30 years. Count percent allowance should be 70%. That is, a factor of 0.7 and multiply by the amount of salary 16000 and get 11200. This number is then add it to the salary, the resulting amount will be equal to 27200. Based on it, carry out the calculation of the pension of police officer.
Before you know the final amount of the pension, calculate an overhead percentage, which is you for years of service. So, in 20 years there are 50% for each additional year added 3%. That is, in your case add 30%. So, the total interest rate will have a rate of 80%. The factor of 0.8 and multiply by 27200 and get 21760 R.